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.