The C and C++ code in many relevant stacks is not going away, and many of us won't be ever be able to use D or Rust regardless of how much we like them.
UNIX clones, Windows, .NET and Java runtime implementation, WinUI/WinRT, Android (regardless of this week's annoucement)
So Microsoft Checked C, Microsoft SAL, Visual C++/clang/gcc lifetime analysers, Frama-C, hardware memory tagging, Pluton sandbox, CHERI,... are all welcomed improvements.
Even if Rust were to fully supplant C and C++ for at least systems programming[1], we should hope that within a few decades it's a risk of being supplanted by something else. To want otherwise is likely to inadvertently want stagnation and/or a language that while likely still improving, is having new technologies and concepts bolted on in increasingly convoluted manner, as they were not and could not have been considered when designing the language originally.
1: I think this is unlikely, if only because I don't see one language supplanting C, I see C's market cannibalized by a few different languages, with C always retaining some use.
If that's what you really wanted, and if we always did that, then you would probably want extensions to Perl instead of Python, since it predated it slightly and was much more popular much earlier.
Instead, I think what you're really asking for is language extensions to the things you are familiar with. Those happen to be things a lot of other people are also familiar with, but that doesn't change that the same strategy results in Perl still getting the lion's share of attention. I, for one, would be perfectly happy with that, as I love Perl, but many people would not, and possibly not for any real technical reason.
Anyone that thinks the case for Rust or D is better served by extensions to C or C++ but thinks that Python is objectively a better language than Perl should probably look deeply at exactly why they hold those views.
P.S. That's not really to say you hold those views. Consider this comment less a critique of your specific statement than slight tangent spurred by it.