It is not useless. AMD would have an inexpensive and clean answer to the Intel mess.That's the point: Intel doesn't do that and there's no reason for AMD to do that since it's useless for production.
Oh and you have to license AVX512 from Intel to use it further increases the cost of the CPU.
And as your logic goes on: why not also include arm instructions to make it more universal? Why not add Power and MIPS and RISC-V to the mix?
Now you're just being silly.