Of the examples given, I think facebook is really the only one that has a decent interface despite it’s complexity. Craigslist is awful and there’s no reason a more streamlined UX couldn’t deliver all the same features. The reason why craigslist hasn’t been supplanted is sheer momentum and a built up reliability. It caters to local stuff in a way that is hard to crack.
And the awful interface of Photoshop is a complete pain in the ass. Have you seen the way it handles swatches??? There’s a reason why so many competitors are popping up. Adobe has gotten lazy and are so entrenched in their own mythology/built up so much tech debt, that they are unable to change PS for the better, but that doesn’t mean there isn’t serious room for improvement.