I think the validation methods mentioned are pretty valid. The one major problem I have found is that there is a very small/distinct set of people who even understand what the validation is all about, and get the idea of developing a quick MVP. And these people are usually savvy/skilled enough to do a quick validation themselves. The opposite end of the spectrum are people who cannot do this, but then they also do not understand that this is not a quick & cheap website making service.

Still, you get to talk to a lot of people. So if you like to bounce ideas (I do), it is an interesting business.