"Bitcoin to zero" is a matter of faith at this point, I don't see it happening and I haven't heard anyone explain a good model for how it happens. US is certainly trying its best to outlaw it. Still won't go to zero.
I think my larger point is if the government wants to go after something, go after fraud--in crypto or "Fintech" or banks or stocks or whatever. And mostly they are! But then they're also leaning on banks to cut off the ability to convert crypto to fiat and that's a bunch of bullshit.
There are even corporations that announce buyback and then don't do it. For stock it's enough to jump up and then random shareholders that accidentally sell their shares in specific window that allows them to profit from such fake buyback get very rich while people waiting for buyback are left with the bucket. It's completely not pump and dump.
Now, some stocks have a real value + speculative value on top. Netflix and many other tech companies are in this state, and the speculative value can go down way more than the real value. But the floor for Netflix stock is waaaaaaay above 0. The floor for BTC and similar is 0, by contrast.
As for pump-and-dumps and insider trading etc - sure, they happen, just as thefts and muggings happen. But they happen a lot less then in crypto-land where they are fully legal, and where, even if they weren't legal, no one would be checking for them.