Here's the quote from Cinema Blend:
"What happens to me is that things are presented to me that are really well thought out by folks that have been doing this correctly for a really long time, and I go like, 'Check.'"
Oh, stop it Robert, we know why you keep coming back ... $$$$
There have been only three Iron Man movies, the last having been released in 2013. There is no evidence that a fourth will ever come to fruition. Why? Again, $$$$. His demands are probably ludicrous because he knows that he is the glue that holds the MCU together, so Marvel's position is, why risk it? We could just pay him an insane amount of money for cameo purposes, just to hold the glue together, rather than pay him $100M for an entire Iron Man movie, or whatever the hell seems to be his asking price these days.