I don't know the team structure but I think it's a lot related to how the new standards are being drafted. They're being done with the big compiler writers helping (also in the open too). This means that the work on each individual extension started a good bit ago even if it isn't in an actual standard yet.

I also think there is some corporate backing in C++ compilers. Like a few internal company people are getting paid to fix this kind of stuff.

Regardless, it's great to see C++ compilers incorporating latest standard features. For comparison, check JavaScript standards implementation in browsers (not sure if it's a fair comparison).

It is a very fair comparison actually, with similar compatibility pains in the past due to both differing interpretation of the standard and plain non-compliance. Things are getting much better lately.