I had found this rebuttal: Ideas are cheap only if you have cheap ideas.

I would argue good ideas are not so easy to find. It is harder than it seems to fit the market, and that is why most of apps fail. At the end of the day, everyone is blinded by hubris and ignorance... I do include myself in that.

They may not be the easiest thing to find, but I'd submit that good ideas are way more common than the skill and resources needed to capitalise on them