Consider one of NVidia's rivals: AMD, who uses an ARM chip in their EPYC line of chips as a security co-processor. Does anyone expect NVidia to "play fair" with such a rival?

ARM as an independent company, has been profoundly "neutral", allowing many companies to benefit from the ARM instruction set. It has been run very well: slightly profitable and an incremental value to all parties involved (be you Apple's iPhone, NVidia's Tegra (aka Nintendo Switch chip), AMD's EPYC, Qualcomm's Snapdragon, numerous hard drive companies, etc. etc.). All in all, ARM's reach has been because of its well-made business decisions that have been fair to all parties involved.

NVidia, despite all their technical achievements, is known to play hardball from a business perspective. I don't think anyone expects NVidia to remain "neutral" or "fair".

An independent ARM that did not manufacture processors was the best outcome for everyone in the industry.

ARM being owned by an organisation deeply embedded in processor design and manufacturing, will now be licensing designs to competitors, as well as getting a lot of intel on its competitors.

ARM supercomputers were poised to take on Nvidia. Now its all one and the same.

As others have said, this will do wonders for RISC-V.

ARM will not be cheaper after this.

More power concentrated in a company that already has a de-facto monopoly over a gpu market.