James, I agree with your following sentiment.

> removing features often means removing actual functionality that someone
> relies on

Hence, the proposal. If one needs to write a function using a
no-longer-supported feature, it should be written in a separate file and
compiled with the appropriate compiler before its resulting assembler codes
are linked with the rest of the program.

I also do not believe features will be eliminated by a whim—I trust the C++
standardization committee in their decisions of what should/could be
removed based on a thorough risk-benefit analysis.

new C++ features are rarely comprehensive *enough* to completely obsolete
> old ones.

If and when the elimination of features is an option, the specifications of
new features would be scrutinized more carefully in terms of their
completeness/coverage and coherency.

Best,
--mehmet kayaalp