FWIW, there are orgs that do that, but they almost always end up being somewhat regional, and... it ends up being a lot of work. FreelancersUnion, in New York, I believe did/does something like that. Some chambers of commerce and similar groups do too, but... it doesn't really end up changing much of the price at all, especially since ACA. (oh, misread, I initially read that as simply just offering a buyers group to get 'group' rates).
You've generally always been able to buy health insurance independently. I started... 14(?) years ago. The ACA, well-intentioned, was hobbled from day one, and my $220/month high deductible plan has morphed in to a $1300/month plan which is still high deductible ($14k/year), has fewer options, and ... well... some pregnancy services will be covered (cis male here). You want a 'low' deductible? You're looking at probably $2k or more for 2 adults. And yes, I know health insurance has an age component - I'm years older than I was then too. $3k/year in exchange for taking on some risk (higher deductible) makes some sense. But base price of $15k/year in health insurance, plus another $14k/year in deductibles means this is essentially catastrophic only, but not really priced as such).
It's all region-based, and even where I'm at, I get measurably fewer options because I live 2 miles over a county line, and 'no one' insures out here. It got worse for several years - I know in NC, there are ~100 counties, and I believe there were more than 30 at one point who had only one insurer even selling health insurance in those counties.
Also.. FWIW, I didn't take it as you didn't care, but yes, freelance workers are generally overlooked, even as the ranks grow. They just tend to be growing on the lower-end of the spectrum - rideshare drivers, door dash delivery, etc. Much easier to just ignore growing segments of society while we pride ourselves on our ability to "get a better job with great benefits!". I'm not in a position of having to choose food over medication, but having to decide between medication or surgery today over funding retirement savings? I've been there, as have some friends of mine. Yes, it comes across as a bit privileged, but privileges are all relative.