Your Marketing Has a Single Point of Failure (And You Probably Built It on Purpose)

Here's a question no one asks in a marketing meeting: what happens to your business if Google changes an algorithm tomorrow?

Not a hypothetical. In 2025, Google rolled out AI Overviews across most search categories, pushing organic results further down the page. Paid click costs climbed another 5% on top of the previous year's 25% surge. Businesses that had built their entire lead pipeline on a single channel watched their cost per lead creep upward with no backup plan.

Most SMEs run 80% or more of their marketing budget through one platform. They call it focus. An investment manager would call it something else entirely: concentration risk.

The Channel Concentration Problem Nobody Talks About

In financial investing, putting all your money into a single stock is considered reckless. You might get lucky. You might also lose everything when the CEO resigns or a regulator changes the rules. Every serious investor diversifies.

Yet in marketing, most small businesses do the opposite. They find one channel that works, pour everything into it, and treat the resulting leads as proof that their strategy is sound.

The numbers show why this matters more in 2026 than ever before. Customer acquisition costs have risen 222% over the past eight years, with an additional 18.4% year-on-year increase recorded in 2025 alone. Google Ads cost per lead now averages $70 USD across industries. When your only channel gets more expensive, you don't have a marketing problem. You have a business model problem.

What Investment Theory Tells Us About Marketing Budgets

Tomlinson's insight is that Modern Portfolio Theory applies directly to marketing spend. In investing, the optimal portfolio isn't the one with the highest-returning single asset. It's the combination that delivers the best risk-adjusted return. Translation: the mix that grows your business without leaving you exposed when one element underperforms.

Here's what that looks like for a typical SME marketing budget:

The "Bothism" Framework: Why It's Not Either/Or

Brand or performance? Both. Short-term or long-term? Both. Google or Facebook? Both, but for different reasons.

The research behind bothism is compelling. Ritson draws on data showing that only 5% of any target market is "in-market" at any given moment, ready to buy right now. The other 95% won't purchase for months or years. You need performance marketing (Google Ads, targeted campaigns) to capture that active 5%. But you need brand-building channels (social, content, video, email) to stay in the memory of the 95% so they think of you when their time comes.

This maps directly onto Byron Sharp's distinction between mental availability and physical availability. Google Ads is physical availability: being findable when someone is already searching. Facebook Ads, email, and content are mental availability: being memorable before someone starts searching.

An SME running only Google Ads is essentially saying: "We'll only talk to people who are already looking for us." That's a fine tactic. It's a terrible strategy. Because it means your entire growth depends on the size of the search market and the price Google charges you to access it.

What the Effectiveness Data Actually Shows

Les Binet and Peter Field analysed 996 IPA effectiveness award campaigns spanning decades to determine what actually drives business growth. Their finding: the most effective campaigns allocate roughly 60% to long-term brand building and 40% to short-term activation.

But the more relevant finding for SMEs is what happens when businesses shift from performance-only to a blended approach. Brands that diversified toward a 50/50 brand-and-performance split held customer acquisition cost growth below category averages and weathered platform disruptions (like Apple's iOS 14.5 privacy changes) far better than performance-only competitors.

The 60/40 split isn't a rigid rule. Binet and Field's more recent work suggests the optimal ratio ranges from 70:30 for newer brands (more brand building needed) to 40:60 for established brands (more activation because mental availability already exists). The principle is what matters: no successful long-term strategy is 100% activation.

Here's how those ratios translate for a real SME:

The Compounding Effect Most Businesses Miss

The hidden power of a diversified marketing approach is compounding across channels. This is something single-channel marketers never experience.

When someone sees your brand on social media, they're more likely to click your Google Ad when they eventually search. When someone reads your email content, they're more likely to convert on your landing page. When someone hears your name from a friend who saw your content, they skip the comparison-shopping phase entirely.

Byron Sharp's research at the Ehrenberg-Bass Institute shows this isn't soft thinking. Mental availability is measurable: it's a brand's propensity to be noticed or come to mind across buying situations. Each additional channel you're present in creates a new Category Entry Point, a new doorway through which a potential customer might think of you.

Sharp is explicit: "Brands grow by being easy to think of and easy to buy." Google Ads makes you easy to buy. Everything else makes you easy to think of. You need both, and the combination is worth more than the sum of the parts.

The Real Risk You're Carrying Right Now

Consider what happens when your single channel hiccups:

• Google changes its algorithm and your ad position drops from 1 to 3. Your cost per lead doubles overnight.
• A new competitor enters your market and starts outbidding you on your best keywords. Your CPC jumps 30%.
• Google rolls out a new campaign type (like Performance Max) that cannibalises your existing campaigns. You spend months figuring out the new system.
• A recession hits and you need to cut spend. With one channel, cutting spend means cutting all your leads. With three channels, you can reduce the most expensive one while maintaining volume from the others.

This isn't theoretical. In 2024, Google's broad match changes and Performance Max expansion caught thousands of advertisers off guard. Businesses with diversified lead sources adjusted. Businesses with Google-only strategies scrambled.

How to Diversify Without Wasting Money

The practical question: how does an SME with a limited budget diversify intelligently?

What This Means for Your Business

If you're running a single-channel marketing strategy, you haven't made a strategic decision. You've made a bet. Bets sometimes pay off. But the businesses that grow sustainably over 3, 5, 10 years are the ones that treated their marketing budget the way a sensible investor treats their savings: diversified, risk-aware, and rebalanced regularly.

The good news: you don't need a massive budget to start. You need a core channel that works, a second channel with a different job, and the patience to measure each one by the right metrics on the right timeline.

That's not clever marketing theory. That's just good risk management.

Further Reading

• Marketing Alchemy: Portfolio Theory - Sam Tomlinson's framework for applying investment theory to marketing channel allocation
• What is Bothism? - Mark Ritson on why brand and performance marketing aren't opposites
• 60/40 Rule 2026: Brand vs Performance Budget Split - Updated analysis of Binet & Field's IPA effectiveness research
• Platform Dependency Risks in Digital Marketing 2026 - Why single-channel reliance is an operational risk
• Diversifying Away From the Triopoly - Tomlinson on moving beyond Google, Meta, and Amazon