>native builds

This is the complete opposite way, actually.

We need cross-compiling that is just as effortless as native compilation.

You should be able to build complex software on a powerful computer and perform costly optimization, then run it on a low-powered device.

It was true in 2005, but still? As I described in another post here, a modern strategy is to get a beefy server than can run the same ABI, then start a docker container and assemble a system from Alpine's package repo, then compile a kernel and a few in-house things, then extract a subset of that into an image. No cross-compile, and most of the useful software is in pre-built binary packages with the compile-time options you would have selected anyway.

Even if you don't have a beefy server of the same architecture, you can probably run it in qemu instead of docker to the same effect. And even if qemu is slow, you can run a build of the kernel and your in-house stuff in parallel on 64 cores and not really be affected by the qemu slowdown.

I'm interested to hear counterexamples, though.

Yocto and Buildroot will compile, from scratch, an entire gcc crosstool chain with standard library suite and headers to build fast and then deploy to your target. This exists.