1. Just because there is Linux, doesn't mean everyone should jump on the Linux bandwagon and abandon all work on illumos, NT, QNX, Fuchsia etc. Focusing everyone on Linux would kill progress.
2. Just because there is x86 or RISC-V, doesn't mean noone should invent new architectures. Apple went with their own and that's what gives them their edge now.
3. Just because there is already Emacs, doesn't mean that all editors should be Emacs mods.
4. And back to compilers, just because LLVM already has optimizers, doesn't mean that other people shouldn't explore other designs for their backends. Especially that LLVM is really slow, and a major bottleneck for new compilers now (see Rust, Zig and Jai e.g.).
If modern tires are considered reinventing the wooden wheels, sure, then reinventing wheel is the main form of making progress. But I doubt that's how people thinking about reinventing wheel, when they use that phrase to mock others of wasting energy inventing something that has already a very-well-working alternative.
Can we be precise here? I never had a memory about a major technical progress being reinventing the wheel.