[bpodgursky]

All sales have an equal amount of buying, and all buying involves an equal amount of selling.

There's never a net movement in one direction.

[p1necone]

You can mine crypto/mint new NFTs/create new coins arbitrarily without paying external currency for them though.

[nightski]

In reality this is devaluing existing crypto relative to other assets. The OP still stands in that money does not flow into crypto. It's not a black hole. Fiat money is being traded for an asset between two parties. The other party gets the fiat.

In other words, you can't create or destroy USD (for example) through a cryptocurrency. You can only affect the cryptocurrency itself. Otherwise we'd have a large problem on our hands...