Spot on, since C++11 the committee has increasingly started to design and add features to the standard without any kind of implementation, only after the standard gets ratified, the implementers eventually find out that the design is broken, or has flaws.

A strange phenomenon akin to the Algol 68 days, and no other ISO based language is taking, where standardising existing practice or having a full test implementation is still pretty much what it being done.

How many export templates, GC, type traits defect fixes, volatile behaviour changes, modules, contracts,.... can implementers still put up with?