I basically disagree with all of that, even with the premise: My C projects are already extremely fast to build. I also don't agree we should give up modularity for whole program optimization, I do not think we should give up static linking, I do not think everything needs to be entangled to achieve this...

The build times we see affecting C++ and Rust are because the type systems of languages is misdesigned. The supply-chain issues we have with the language-level packaging manager downloading source instead of pre-compiled binaries from curated repositories are also related to this. I think we need leaner, simpler, and better modularized software. Not whole-program optimization which is only necessary because of the monomorphized gigantic intermediate results created for badly designed languages, which then needs to be reduced again in a costly process.