"Dry testing" in software is traditionally called "vaporware". It's been found to be an excellent way of taking sales away from competitors with actual products on the market, who are hampered by not being dishonest scumbags and only being able to get away with claims that are feasible.
I'm probably a minority, but your reputation with me is toast if I find out you ever did dry testing.
I understand the sentiment, but I'm curious how you personally judge an expensive idea without spending the 6 months to develop it? A simple web app may take a weekend, but that's not the only type of minimum viable product, unfortunately.
Market research still works when you admit to your audience that's what you're doing. They say it's somewhat less accurate that way, but even if that's true it doesn't entitle anyone to throw chaff into the system that allocates resources to us.
I'm probably a minority, but your reputation with me is toast if I find out you ever did dry testing.