The stock market is comparatively highly regulated - Ponzi schemes are explicitly illegal there, for example. The US stock market regulatory body, the SEC, actually has teeth and uses them.

There is nothing comparable in crypto - so it's a sea of crime.

If you look at the early history of stock markets - pre-regulation - it looks similar to current cypto markets - crime as far as the eye can see. This eventually caused regulation to happen. But everything is playing out much faster now, because it's all digital.

It's also much easier to run a crypto scam than a classical stock market one - way less work and time investment - so the bar is much lower. So, in the absence of much in the way of consequences, we would expect far more scams in crypto, because it's lower effort.