One more photographic thread for you

A dear friend of mine, in my opinion excellent photographer, claims that even today he would not buy a FF camera with a higher resolution sensor than 18-20 Mpx, since he believes image quality, in terms of noise caused by the smaller and closer pixel sensors, would be lower.
Of course, he says he personally does not need the other obvious benefits deriving from a high Mpx sensor (large prints, cropping, etc.).

Based on what I read around, his view seems a bit outdated. What is you take, considering the most recent camera bodies and sensors? I realize this may be a fairly complex topic, but that is precisely why I posted here.