Not, really as a one-line change to the source code can easily change this behavior. In short, you can run proprietary modules easily, on all hardware the real kernel supports. Try it. No harder than a recompile.
You just can't distribute kernels with proprietary modules outside your organisation, and you have to upgrade and support the modules yourself. Which, I'd bet, effectively means Google, Meta, Samsung & Oracle and other behemoths can and do use proprietary modules.
The main complaint is that, say, any kind of small hardware vendor effectively cannot have proprietary modules in the kernel.
And this is generally regarded as a very good thing, a nice way to deal with a very real threat to open source.
