You have not given a single strategic imperative for the Nvidia acquisition. They have full access to the IP.
The real issue here is Nvidia are hugely overvalued thanks to the vagaries of the US tech stock market and the ‘irrational exuberance’ that surrounds it. Just a short while ago, Tesla was valued at over $800 billion, Apple has topped a trillion and now Nvidia on $16 billion sales at >$300 billion. As a result that have a while loymtvof stock value burning a hole in their pocket and are looking for something to buy. Unfortunately, ARM is in the frame.
When you make an acquisition, you have to ask whether it positions the combined business uniquely, will is cannibalise existing business (in this case almost certainly because ARM’s great appeal besides its IP and eco-system is that it is independent), will it move the stock price in the right direction, will it improve EBIT, what are the synergies etc etc. A typical M&A will invoke dozens of considerations like this.
More investment into ARM? They own the mobile phone space - Apple, Samsung and almost every other brand (many in China where I worked for a few years). They’ve seen off Microchip in the general purpose 32 bit uC space and dominate IoT applications, Bluetooth etc.
There’s nothing stopping Nvidia copying the existing ARM model right now. They don’t need to buy ARM to do that.
Nvidia stock price will moderate down (as will all semiconductor companies in the coming months as the chip shortages abate) and with it a more realistic valuation.
(What do I know? Been involved in a few M&A’s. ;) )