The problem with this way of thinking is that existing markets are probably efficient enough - meaning all easy ways to make a lot of money have already been exhausted. This means that any idea that you generate by encountering a problem and thinking of a solution is probably either too hard to implement or will generate relatively puny revenue stream (nothing to sneeze at, but probably not of much interest to VCs and founders chasing big bucks).

What's the alternative? To wait for tectonic shifts in overall environment and circumstances, look for vacant ecological niches and pounce when you see one. To the outside view this will look exactly like a founder who doesn't know what to start up.

Here is an example I like: John Carmack. The conventional view is that he is a brilliant game programmer (which is undoubtedly true). But the alternative point of view is that his shtick was to capitalize on the period of incredible advances in consumer hardware. Each of his games fully showcased what the best hardware of that time was capable of (order of magnitude more than the previous generation) which made them instant hits. Not coincidentally, he quit making games around the time this period of advancement stopped.

Here is a post by @defmacro making a similar point: http://www.defmacro.org/2015/02/25/startup-ideas.html