I am have nothing against nor am I a huge fun of NFTs They are new and still the best use cases hasn't been discovered. But there are few things that you mentioned seems to be wrong about NFT.
NFT's are unique pictures stored on a Blockchain and it gave a big hype around NFT's so far.
But please do your own research what is a NFT. It is just a picture stored on a blockchain and every day new pictures are launched.
It is not really scarce when always new collections are launched.
NFTs aren't just only "pictures". They can be anything. They are scarce as long as unique and only one of a kind NFTs are minted.
Over time, only very few people will buy such pictures and NFT's will get very hard to sell because nobody wants to buy old NFT's in a few years. Why should someone still pay high prices for such pictures?
Wouldn't "older" pictures be more rare and cost more? The older it is the more people will want to buy. This is how it usually works. The newer ones are also cheaper until they age.
Over time, only very few people will buy such pictures and NFT's will get very hard to sell because nobody wants to buy old NFT's in a few years. Why should someone still pay high prices for such pictures?
I thought they buy NFTs not as an investment but to showoff their wealth and to "uniquely" own something?