For those stuck in the past yes, they have replaced it with a Rust based toolchain, as is so fashionable nowadays.

Luckily DX is much better now with Turbopack as a bundler. First they improved the dev server, now with Turbo builds the production builds are faster as well. Still not fully stable in my opinion, but they will get there.

It's also wise to use monorepo orchestration with build caching like Turborepo.

They did well on the turbo stuff, no doubt about it.

The main bottleneck with big projects in my experience is Typescript. Looking forward to the Go rewrite. :)