It's all the hype and when the trend is offset you would find it hard to sell them at high prices like the current scenario.The investors are ready to pay such huge amounts to buy some artworks was never imagined before or say 1-2 years back but now it's all happening in reality.
It's just like back in the tulip bubble. As long as there are people who want to pay (huge amounts of) money for goods, these goods will be traded. The problem I see with NFTs, however, is that here too the hype will probably collapse completely in the near future and you probably won't be able to put your expensively purchased images up for that price for a long time.
There is a bit of a difference though. In the tulip mania, people bought tulips, like literally tulips, it is nothing original, I could spend a million dollars right now and can build a farm that is enough to cover all the tulip needs of most regions let alone nations, it is simply just tulip. Whereas this is art, art could be worth 1 dollar, could be worth 100 million dollars, it is subjective and it is not something that is set in stone.
You can just copy paste it, I mean you "could" but it wouldn't be yours, it would be other peoples art that you are just copy pasting but ownership belongs to just one person. Very recently, a famous person sold a drawing of himself for nearly 5 million dollars, do you believe that could ever worth that much money? Of course not, but someone did, it doesn't have to be so that you could resell it higher, it is simply just something a rich person did, that is all there is to it in art.