Kevin Costner Didn't Need to Think About GTM While Building. You Do.

For the few uninitiated - most likely the Gen Z founders among us - here's the origin story of one of the startup world's favourite clichés.

In the 1989 film Field of Dreams, Kevin Costner plays a farmer who hears a mysterious voice telling him to build a baseball field in the middle of his cornfield.

He does. And, against all reasonable expectations, people come.

No customer discovery. No distribution strategy. No selling.

Just a mysterious voice assuring him that if he built it, they would come.

Most startup founders don't have that luxury.

Yet we keep seeing versions of this play out in early-stage startups.

A founder does some customer discovery, identifies a promising problem and gets building.

And now that writing code has become so much easier, they can build an astonishing amount before they've worked out how they're going to sell any of it.

Eventually, they move into selling mode. In some unfortunate cases, they even bring in someone else to sell the product they've built, believing it's ready for market.

And so, the product meets the harsh winds of commercial reality and starts to reveal its hairline cracks. Sometimes deep fissures.

They find that customers need capabilities nobody thought to build. The buying process looks nothing like the founder imagined. The price doesn't work. Getting customers onboarded turns out to be a project in itself.

The problem isn't that they didn't do customer discovery. It's that they treated building and selling as two separate stages.

Product discovery and GTM discovery aren't separate exercises

We've become reasonably good at talking about product discovery.

Understand the customer. Validate the problem. Test assumptions. Build something small. Learn before committing significant resources.

But how often do we apply the same discipline to go-to-market? After all, GTM is full of assumptions that need validating too.

Who are the customers we can realistically reach?
What triggers them to look for a solution, and how will they discover ours? Who makes the buying decision?
How will customers purchase, access and get onboarded onto the product? What capabilities do we need to support that journey, including billing and payments?
And given what it costs us to build, deliver and acquire customers, how should we price the product to make the business viable?

The answers can fundamentally change what we decide to build.

What you learn from selling should influence what you build

Imagine you're building a workforce planning product.

Your early customer discovery suggests HR leaders have a genuine need for it. They're enthusiastic about the concept, and you've identified some valuable capabilities.

So you build.

Months later, you start trying to sell it. Only now do you discover that while HR will use the product, Finance controls the budget.

HR needs workforce planning capabilities that help them do their jobs. Finance, as the economic buyer, needs a compelling business case to approve the purchase.

Does that mean you need to build additional features for Finance? Not necessarily.

Their requirements might be satisfied through pricing, ROI evidence, reporting or a demonstration of the product's value.

Some of those might require additional product capabilities. Others might be addressed through your commercial proposition.

You might also discover that customers expect integrations, security assurances or supported onboarding before they can adopt the product.

Some of these discoveries change what you need to build. Others change how you package, price or sell it.

And crucially, you could have uncovered them before spending months building.

Why founder-led sales matters

This is why founder-led sales is so important in the early stages. You can't simply hand a product to a newly hired salesperson and say, "We've built it. Now go sell it and bring us paying customers."

At this stage, every sales conversation is an opportunity to learn.

Why did a prospect show interest?
What stopped them from buying?
What did they expect the product to do?
What would make it valuable enough to pay for?

When founders step away from these conversations too early, customer objections get reduced to feature requests. Buying behaviour gets interpreted second-hand. And the people deciding what to build lose access to the context behind those decisions. That context loss can be expensive.

Founder-led sales keeps the feedback loop tight while the product and its route to market are still taking shape. And the learning flows both ways. Product discovery might reveal a valuable use case for a different customer segment, forcing you to rethink your pricing, positioning and route to market.

What you learn about the product changes how you sell it. What you learn from selling changes the product.

So, what should happen earlier?

I'm not suggesting that startups need a fully developed GTM strategy before they start building. That would rather miss the point.

They need to start testing their commercial assumptions while they're testing their product assumptions.

While interviewing customers about their problems, ask how they currently discover, evaluate and purchase solutions. Find out who approves the purchase and what might prevent them from proceeding.
Once you have a credible product proposition, start testing whether customers would actually buy it, even before it's fully built. Put a price in front of them, explore what they'd need to see before committing, and look for evidence of genuine purchase intent rather than polite enthusiasm.
Map out how a customer would go from first hearing about the product to actually using and paying for it. Where would they need help? What capabilities would the product need to support that journey?

Feed those findings into the roadmap, alongside what you're learning about the product itself. You don't need every answer on day one. But you do need to start asking the questions.

Don't leave half the discovery until launch

The problem with build it and they will come isn't simply that customers might not come.

It's that if you haven't worked out how customers might find, evaluate and buy your product, you may not even know what you should be building.

So don't finish building before you start figuring out how to sell.

Unless, of course, a mysterious voice in your cornfield has promised to take care of customer acquisition.

In which case, I'd love an introduction.