Is it competition that causes Apple and Nvidia prices to stay high?
Yes they have no competition. Nothing significant anyway.
Instagram and many other apps
require you to have a Smartphone. It has a desktop application but it's complete trash. Many sectors do not have a PC sector at all. Zero. Nada. Wintel ecosystem is dying. Very slowly, but it is. Now the representative company of Wintel, Intel itself is in serious trouble. $46 billion debt with ~$50 billion total revenue. Hey, it looks like Intel is representative of average America, having 90% of revenue as debt vs US government having 120%.
That's a real threat. I'm forced to install it on my phone if I want that app, and many, many do. I can't use Telegram without authenticating it with the phone first either.
Apple created all this. And they are still absolute monopoly. Sure they might have only 20% or so of the volumeshare, but where do you think all the money goes? The profits? 20% market, 50% revenue share, and 85% operating margin share. Now take the leftover, and assume that much is taken over by something. The dozen or so vendors are fighting for the scraps.
Nvidia is similar too. Aren't they the highest valued company now? Sure that's all monopoly money, propped up by endless money printing. But still.