I throw the question to my audience in this short post.

I have met many startups who focus on product development. They told:

The market is clear. The problem is obvious. We don't need to validate it.

We cannot spend our precious time talking to people to discover that what we do is exactly what they want.

If we talk to potential customers we have to show something that works, otherwise we are not credible.

I also discovered that finding Problem-Solution Fit become relevant only when product launch miserably fails. With no excuses on lack of quality, those who don't blame the "uneducated" customer, will accept that Customer Discovery is an essential step before even think to start the product development.