For Nvidia that isn't actually the case at all. It's not electricity per se which is important, it is heat. The new(er) GB200s require liquid cooling because they put out so much heat. Virtually 0 datacentres have liquid cooling to each rack, so rollout has been extremely slow (basically have to build new datacentres from scratch).
The problem Apple has got is they are far, far too reliant on TSMC. It may be worth Apple buying Intel just as an insurance policy. It would be less than 3% of their market cap.
If TSMC goes down/decides not to serve Apple in the future (eg NVidia buying up literally all of the capacity because their products are so much more valuable than Apples)/some other TSMC related black swan event, Apple is close to toast. They get 70-80% of revenue from hardware and could end up with no hardware to sell. Every device they have cannot work without TSMC.
A great book on this btw is Apple in China by Patrick McGee.
Nvidia on the other hand need the latest tech to squeeze the most performance out of their chips for AI companies.
So if TSMC went down tomorrow, you can't exactly phone Intel up and say "hi we need 1billion m-series chips a year, starting in a few weeks?"
If they owned it they could start doing that in the background.