Yeah that's the point, both you Gerd and Godo said things I think too: a) Mourinho can actually choose where he will go, he won't be short of suitors; b) His choices aren't necessarily the clubs who pay him more, but the clubs who offer a big budget for him to work with, therefore increasing his chances of success.
The idea of not winning stuff terrifies Mourinho, so now that he's reached these heights in his career, we only see him managing the wealthiest clubs in the world. I don't think we will see him embracing a project that is a big sporting challenge where he will have to build up from the ground and upset the odds somehow.
As for United, I do remember him hinting at succeeding Ferguson. Maybe it was best for him that he didn't. A big pressure even for Mourinho.