The problem with this is that had they made the exact same post on Hacker News an hour earlier or later there's a good chance it would have gotten no more than two or three upvotes and never even made the front page. If that had happened, which in fact is probably the most likely outcome given repeated experiments, does that mean that it was a bad business idea? (For example, this is a great blog post but it's getting no upvotes, and so most likely no one is ever going to see this comment.)

I think the first idea was probably just a bad idea and they could have figured that out on their own or by asking someone.

The second idea, if they had gone and asked professors, they probably would have gotten mostly folks telling them it was a great idea. But in fact that was still a bad idea also.

And the third idea was a legitimately good idea, but I think the validation they got was as much due to luck as anything else.

So I like the idea in theory, but it's trickier than it sounds. A lot of people make the mistake of not doing any market valuation. But even if you put in the work to do this, there is still a very high value to building something that has a lot of optionality going forward.