That depends on what you mean by "independent." There is a space between standard faculty and hermit researcher. Depending upon the field, you can do research

That depends on what you mean by "independent." There is a space between standard faculty and hermit researcher. Depending upon the field, you can do research, publish, go to conferences, have a network of peers, without being standard faculty. I know research professors who have very few of the standard faculty obligations, for example. I also know people who do research entirely on private funding, but this almost always requires significantly more than just savings from retiring early, and they still stay part of the academic community. I agree that it is not something that should be advertised as an option, because it is very rare, but it does exist.