Kernels now written in Mojo were all in hand written in MLIR like in this repo. They made a full language because that's not scalable, a sane language is totally worth it. Nvidia will probably end up buying them in a few years.
I don't think Nvidia would acquire Mojo when the Triton compiler is open source, optimized for Nvidia hardware and considered a industry standard.
Nobody is writing MLIR by hand, what are you on about? There are so many MLIR frontends