That's not the tldr I got from this at all. The solution to having bad ideas is to stop and ask yourself if an idea is bad before you pour months or years with of work into it. Everybody has bad ideas, and everybody has a few good ones. Filter your ideas, instead of jumping on the first idea you come up with just because you want to found a startup, any startup. Don't waste your time.
No. They work on ideas they never really tried to think through sufficiently to know if those ideas are good or not.
And this is very, very common, at least in people I happen to know. It's hard to look at yourself objectively, we all know that - do you think that looking at your ideas objectively is easier?
What kind of advice is that? This is like telling kids to "be like Mike [Jordan]". Yeah, I guess it would be nice...but, that's not a strategy.