I can see what you mean here. I feel like this often applies to SaaS products and Network companies like Facebook, where forerunners in the field have validated the need for something in the market, but failed from a technical or a distribution angle rather than a product perspective.

Its a very good point. I think the 'lean' movement is really meaningful when you're talking about big engineering innovations (where the alternative is often between doing a big build or doing manual work) rather than a network or service business where the concern is actually around the quality of the network or service you're providing, which can't be easily faked or tested.

Not sure what you mean by 'validated market'? How can you have a 'validated market' without having a 'validated product'? A landing page, or a competitor's customers, don't quite count as a validated market.

A validated product is simply a product that people find of significant value such that they change their behavior to use it. That can be either paying for it, or just replacing some existing tool in their current toolchain.

If the point of an MVP is to reduce product risk (and I think it is), then yes, products where you're essentially certain that if you build it they will come don't gain anything from an MVP -- you've already solved the problem it addresses.

The people who are beating the drum for "always do an MVP" suspect that founders systematically overestimate how well they've figured out the market and how exactly they've nailed what their customers will want. I think they might be right, there's a "whistling past the graveyard" habit that optimistic startup-types take on where they avoid bad news in the hope it'll go away.