From a technical standpoint your are correct. From a practical standpoint there is something we all are not seeing.
The industry has customers that place a lot of value on relative anonymity. There isn't anything inherently illegal, immoral, or wrong with 'dark money' either it really isn't anyone's business what anyone else invests their personal wealth in. (beyond basic tax law enforcement etc, which yes privacy does complicate)
The industry also must certainly be aware they make quite a lot of money off players who are in fact sanctioned, using their platforms in complex laundering schemes and the like.
I don't see anyone who is running and IB, brokerage, or exchange wanting to just make all that go away. Maybe I am to cynical but if the people in those positions were really the types to say "hey we are willing to make less money, for the greater good" well there are at lot of things like know your customer standards and the like they'd have beefed up voluntarily already.
So I am left with there is a plan here we have not seen yet, like charging premiums for coin blending services or other various proxy ownership games like invite only trading of in house assets off chain.
One thing I am certain of nobody is trying to give the SEC radical transparency out of the goodness of the big hearts