My point is, if you can abstract the underlying architecture, you can replace it. It's difficult because most complex abstractions leak, but it has been done in the past. That Javascript virtual machine written in C++ could be re-written in Rust.

So, even if displacement means "you are not even allowed to use C/C++ as a target language", and "you are not even allowed to use OS services written in C/C++", we can still "displace" C and C++. It won't happen any time soon however. I believe we need to wait for something like mainstream FPGAs.

The problem with current processors and C/C++ is, they tend to be optimized for each other. If instead we had something like an FPGA running at desktop speed, programs would be compiled to logic gates instead of being compiled to assembly. This would dig a grave for C++.