But how C++ was coded to older Standards was not wrong at the time. That code was chosen judiciously according to features of the language as it existed then, and our understanding of it and our world.
Changes in languages are not random. Every last change in each new C++ Standard was in response to recognition that code would be better using the proposed change. Failing to use the new features as intended, after, would amount to choosing not to write code better.
Rust started at a snapshot of how problems of coding were understood at one time. Our understanding today and the world we program for have changed markedly from that time. Both will continue changing. What is good Rust will also change as the world, our understanding of it, and the language all change.
Failure to adapt is just failure.