Agree that proof of implementation and real world experience should be a requirement for standardization. But it is a catch-22: implement it's are probably not always too keen to spend time on a large feature if it is not clear that it will be standardized.

In practice both clang and VS have had some form of module support for quite a while, but the final standard ended up being different from either implementation (shaped by their experience, and certainly with inevitable last minute inventions).

I wonder if for some features the committee should vote for general guidelines, the delegate a third party (one or more implementors) to come up with both an implementation and standardese with the understanding that it will be fast-tracked in wit too much bike-shedding