From Zero Marginal Cost to Zero Users

A few weeks ago, I wrote about how the marginal cost of entrepreneurship just hit zero. The thesis was simple: AI tools have removed so much execution friction that a solo founder can now build a real product in days instead of months. No team. No funding. No permission needed.

Everyone I showed it to was excited. The post got traction. People agreed.

But there was one thing the commenters kept saying that I quietly filed away:

"The hard part was never the code."

They were right. Here's the honest next chapter.

What I built

Together with Tim Van Landeghem, I built OfferteAudit — an AI-powered tool that audits renovation quotes for Belgian homeowners. You upload a quote for solar panels, a heat pump, or roofing work, and within minutes you get an independent report: Is the price fair? Are there hidden risks? Is the installer legitimate?

The product works. It genuinely works. The AI catches things that most homeowners would never spot:

• Wrong VAT rates — we regularly find quotes charging 21% instead of the legally required 6% for homes older than 10 years. That's €700 to €1,500 in overcharges.
• Inflated production estimates — installers quoting 7,200 kWh/year for a system that will realistically produce 5,800. Makes the payback period look better than it is.
• Missing certifications — installers who claim "15 years of experience" on their website, but were registered in the business registry 3 years ago. No RESCERT certification. No VCA safety certificate.
• Hidden costs — AREI electrical inspection not included. Grid registration not included. Mounting system not even specified.

We showed it to friends. To family. To fellow builders. Everyone said the same thing: "This is great. My neighbor/brother/colleague just got a quote, they should use this."

And then: nothing

Zero signups. Zero audits from strangers. Zero.

Not "low traction." Not "slow growth." Literal zero.

The product was live, deployed on Azure, fully functional — and completely invisible to the world. Like opening a shop in a basement with no sign on the door.

The distribution problem is not a bug

Here's the thing I underestimated: building the product was the easy part.

With Claude as our co-pilot, we built the entire stack in weeks. .NET backend, Blazor frontend, GPT-4o for analysis, QuestPDF for report generation, Azure deployment, email notifications, multi-language support. A one-person team shipping what would have taken a 4-person team 6 months just a few years ago.

But the AI that helped me build the product can't walk into a Facebook group and have a genuine conversation with someone who's stressed about their solar panel quote. It can't build trust. It can't be a known name in the renovation community.

And trust is exactly what you need when you're asking someone to upload a financial document to a website they've never heard of.

What I'm doing about it

There's no clever growth hack here. No "one weird trick." The playbook is old-school, manual, and unglamorous:

• SEO content — writing blog posts in Dutch targeting the exact questions Belgian homeowners Google: "What's a fair price per Wp for solar panels?", "How do you compare solar panel quotes?", "What should be in a heat pump quote?"
• Community presence — joining Belgian Facebook groups and forums where people ask about renovation quotes. Not spamming links. Actually helping, and mentioning the tool when genuinely relevant.
• Manual outreach — asking everyone in my network who's renovating or knows someone who is. One conversation at a time.
• Feedback loops — following up personally with every early user. What was useful? What wasn't? Would you recommend it?

The goal isn't scale. It's validation. Will 20 strangers use this and find it valuable? That's the question. Everything else comes after.

The real lesson

In my previous post, I celebrated how AI has democratized building. That's still true. But we left out the second half of the equation:

The marginal cost of building hit zero.
The marginal cost of trust did not.

Every AI-enabled solo founder will eventually face this same wall. You can build anything now. The question is: can you get anyone to care?

We don't have the answer yet. But we're doing the work to find out. And we'll keep sharing what we learn along the way.

Try it yourself

If you know anyone in Belgium who recently received a quote for solar panels, a heat pump, or roofing work — send them to offerteaudit.be. It's free, independent, and takes 3 minutes. They'll get a report that might save them thousands of euros.

And if you're building something with AI right now: enjoy the building phase. Seriously. It's the fun part.

The real work starts when you close the IDE.