I mean, most legit exchanges are not 'rooted' in scams, even if some of their employees take advantage. The only way you could say Coinbase were 'rooted' in that is to assume your premise: that crypto itself is a scam.
I don't think most exchanges are rooted in scams no - I'd say they're rooted in a greater fool scheme, given that the main purpose of buying crypto is to sell it for profit and it isn't really used for exchange outside a few niches like darknet markets.
Then I think you are assuming your premise/begging the question. You constructed the conditions in a way that leaves no room for a valid example. If you think crypto itself is a greater fool scheme then purely definitionally there can be no example of a non-greater-fool-rooted crypto business.
This is what I've observed, it's not a prima facie assumption. I was initially optimistic when bitcoin came about. Most of the industry seems to be based on speculation and selling "x but on the blockchain" solutions to nonexistent problems. I also know people who are trying to use blockchain tech to solve real problems, but they're in the minority.
