That was done years ago. The SEC cracked down on initial coin offerings back in 2018. They're still working down the backlog.[1] The "cyber" enforcement staff was doubled a few months back to catch up.
The SEC does not consider Bitcoin to be a security because there's no "common enterprise". It's distributed more like a mined commodity. Miners are competitors. But where there's an issuer, or "minting", or "pre-mining", or anything like that, you can buy it, and it's expected to go up, it's clearly a security.
Etherium is in an interesting position with the shift to proof of stake. That may have made it a security, because it's now controlled by voting owners, just like a stock. So now there's a "common enterprise", unlike in the "mining" phase.
The big question now is exchange regulation. Are Bitcoin exchanges and brokers going to have to register with the SEC, pay for and be covered by SIPC insurance, and be regulated by FINRA? After FTX, that's probably coming. FTX acted like a retail broker, after all. Nobody runs Super Bowl ads or buys stadium naming rights for something sold only to institutional clients.
The law in this area looks at the economic realities, not the form. If it looks like a security, is marketed like a security, and is bought and sold for the same reasons as securities, it's a security. Doesn't matter what you call it.
[1] https://www.sec.gov/spotlight/cybersecurity-enforcement-acti...