I think this goes to the heart of the matter:
First, of course, the SEC wants approval from its congressional overseers and from the general public.
It doesn't just "want" approval from Congress. It must have it, because its budget depends upon it. In the present climate, Congress tends to frown on regulation, but neither does it want to see blatant crooks get away with what they do, because that pisses off the public. So measures that might prevent fraud aren't really encouraged, but vigorous enforcement actions against bigtime perps are.
And of course it's those actions that result in settlements or judgments the perps actually pay, because they want to stay in business. Congress is pretty ignorant where penny stocks are concerned. It seems to confuse them with "small business", which naturally is "the backbone of our economy". So the SEC shrugs; pennies are already a low priority for Enforcement.
As to bitcoin and other cryptocurrencies, the SEC is trying to get a grip on it now. Obviously they should have started earlier. We have yet to find out what Congress thinks of cryptocurrencies, but I'd be willing to bet hardly any of them have a good understanding of the issue.
And finally, priorities at the SEC shift with every change in administration. New Chairmen invariably want to concentrate on different things, and have their own pet projects. That, no doubt, can make life difficult for people in the field who deal with day-to-day issues.