It is not "custom embedded tooling"! It is tooling you run on your main machine to build a custom distro. Imagine you follow the "Linux from Scratch" tutorial, then start writing scripts to automate parts of that, and eventually create a framework that allows you to create a custom Linux from Scratch. After years of work you may end up with something that looks like Yocto.
The whole point of using Yocto is that you want a custom distro. You could build a totally "standard" distro with Yocto but... at this point you can also just use Gentoo or Debian or whatever works.
I agree that vendors should upstream, but into packages that are upstream of even the distros. It's not like x64 where the same binaries can support multiple systems. My product OS can't even boot on the chip maker's devkit and it's impossible to make a binary that works on both.
A vanilla distro doesn't want to support a platform with a few hundred thousand units and maybe a few dozen people on the planet that ever log into anything but the product's GUI. That's the realm of things like OpenWRT, and even they are targeting more popular devices.
I understand the hobbyist angle, and we don't stand in their way. But it's much cheaper to buy a SBC with a better processor. For the truly dedicated, I don't think expecting a skill level of someone who can take our yocto layer on top of the reference design is asking too much.
There's a lot more to Yocto than just building the kernel. It's still useful when kernel support is upstreamed, such as including vendor tooling and test programs.
Upstreaming also takes a very long time and is usually incomplete. Even when some upstream support is available you will often have to use the vendor specific kernel if you want to use certain features of the chip.
Nobody can wait around for upstream support for everything. It takes far too long and likely won't ever cover every feature of a modern chip.
This comment makes zero sense. It's a meta-distribution: it builds a custom one for you. Professional custom embedded distros are a different beast altogether from the vanilla distros.
