FTX was an exchange though, they didn’t operate a network as far as I know. So on a centralized exchange itself there’s no transparency because they take the coins, put them in their own wallet and trades happen internally, but in theory you can still see how much of each give the exchange has in its wallet as the wallet itself is public. There’s decentralized exchanges as well that just facilitate the exchange of coins between people but it’s all happening on the network.

The way I see it for a stock exchange you would want that second option (decentralized exchange so it’s transparent) and the different stocks would be what are called alt coins on the existing networks, but only the central authority could create new ones instead of it being open bar…