I'd say we should be careful about using demeaning language or making assumptions about anyone in the business. I've known some SPs who prefer to work for agencies; they don't have to maintain a website or post ads, can keep a low profile, and sometimes have full-time jobs. Obviously some agencies are better than others in terms of respecting their SPs. And unfortunately I've known indies who are in exploitative situations; as LL has repeatedly shown, being an "indy" doesn't necessarily mean autonomy or good working conditions.
You're 100% right, a lot of SPs prefer to work for agencies or spas for various reasons and I think their choice should be respected.. Indies who are being exploited by someone are not really indies.. However yes it's true that even if we work for ourselves as indies we don't necessarily have autonomy and good working conditions. But let's not lie to ourselves here.. Employers are taking a huge cut at agencies and there are things that go on in these workplace environments that are unsavory, sometimes girls are pressured to do certain things too.. I'm not going to elaborate but a lot of friends have confided things about spas and agencies that I absolutely don't want to share here.
I've never worked for an agency and I imagine some are better to work for than others, same thing with spas

When I worked for the spa I worked at the longest, I got paid very little but I was not forced to do GFE for barely anything more, for instance. The working conditions were not always fun, but the boss I had, who is a man, never pressured me to do anything I didn't want to do. He is actually an easygoing person. I definitely have traumatic memories working there for various reasons but overall I feel like I had agency, I decided what my schedule was, how much I charged for extras, etc. It all depends.
There is an agency that advertises here who's manager reached out to me last year, and honestly they would be the agency I would choose to work for if I had to. I also really liked their responses to certain conflicts here. It's complicated, as you're saying. But as a mid-range indy, I have a lot of control over what is going on. It wasn't like this at first and there was an important learning curve particularly in the last 2 years, but I get to keep my wages, no one is telling me what to do, I get to create an image that attracts the clients I want and it works.. I don't have to see several clients in a row, which can be really difficult physically and mentally. I can offer a better service.