Apple's PE ratio is half of Netflix and Amazon's, despite them being in a clearly dominant position. I think tech is probably overvalued, but if the market's right about tech (and in the end that market is usually right), the only reason Apple isn't a $6T company is because investors simply don't have enough money to throw into them.

By dominant position I mean Walmart.com is 90% of what Amazon is, HBO Max is imho better than Netflix, Bing/DDG is as good as Google for most searches, etc etc. No company is within 1% of replacing Apple.