I don't think you understand what the word scam means. Sure, there are various different projects in nft that fail either because of incompetence, or because they are scams. But that doesn't make erc721 or ERC-1155 scams. They are just protocols that can be used as any other good tool, for making scams or making a difference.

It's like asking that is web2 a scam. Sure, there has been many scams in web2.0 but it's a tool just like web3.0