I agree that there were a lot of failed projects, perhaps more than 80%. But if you learn to choose promising projects the profit even from one good project can be large.
Two years ago, some projects have profits tens times higher than the initial investment, but now you should not count on this. The crypto market has changed and most likely there will be no more such rapid growth.
Everyone wants on $ 1 investment to get 10-100 or 1K$ profit. This has really happened before, but I don't think it can happen again. Excess profit is possible, but in 1 project out of a thousand and not for all holders, but only for a small part of them.