People,who deposit money in the banks aren't traders and they don't expect huge ROI.
You have to compare fiat money investments in trust/hedge funds vs. coin deposits in crypto exchange platforms.
First, as I said it before, if we do this is will be even worse for cryptos.
Second, it will also be wrong because a lot of those funds just how the money of exchanges is held in banks also hold their money in banks account, investment funds don't keep money in their safe
But, and this is the part I really don't like, a lot of people theat exchanges like banks.
In real life I have very few friends who own cryptos, and not even counting the fact that they are shitcoin investors, they have most of their coins on binance, not in their personal wallet, and two of them (out of three, lol), don't even have a wallet.
I doubt we would eve find a statistics like that but I do sometimes wonder how many people have coins sitting there in online wallets unmoved for months or even years.