Would you rather have TSMC in control of ARM? Maybe have access to new architectures bundled with a mandate that you have to build them on TSMC's processes?
How about Samsung? All of the fab ownership concerns of TSMC plus they also make basically any tech product you care to name, so all the integration concerns of NVIDIA.
https://asia.nikkei.com/Business/Technology/Key-Apple-suppli...
Microsoft? Oracle? None of the companies who could have afforded to pay what Son wanted for Softbank were any better than NVIDIA.
There are a lot of good things that will come out of this as well. NVIDIA is a vibrant company compared to a lot of the others.