This makes no sense. nVidia is already transitioning away from ARM and shipping RISC-V controllers in their GPUs. They already gave up on Denver, their high perf ARM server chip. Why would they buy ARM?
Pure uneducated guesses from me: maybe the reason for giving up on Denver would no longer be a reason if they owed ARM. Or maybe they see a future use of ARM's tech that will either benefit them to own, or that scares them that ARM competition (or competition from other companies working with ARM) in a current or future area. Or just that they believe ARM is a solid business that will make money whoever owns it.
But I don't have a clue if it's a good idea or not.
They're using RISC-V for their micro controllers. I don't think we have any reason to believe they won't stick with ARM for application cores. And they've tended to ping-pong between Denver cores and standard ARM cores so I wouldn't entirely write Denver off.
Controlling the ARM holdings the company is very different value prop than a single arm chip .
When they made those decisions ARM wasn’t available for buying, SoftBank was ok top of the world didn’t have to sell anything . A year back do you think SoftBank would consider a proposal so close to their purchase price ?
But I don't have a clue if it's a good idea or not.