Maybe it's very different where you live than in France, but what you say clearly isn't true here. For more than the top 1% gets real freedom. Getting into CNRS or Inria or other public research institutes is hard because it's very competitive, but it's not impossible. And then there are positions at universities which are reputed to be less hard to get (depending on the uni, of course) since there are more of them.
Concerning the pay, I question what you call "little". Salaries in public research institutes in France may be little compared to what you could make at a good position in the industry and given your diplomas, but it's certainly not a bad salary in the sense that you can live off of it with reasonable comfort.
Dekhn is calling you out on your qualitative statements: where you live, in your field, in your own mind and to the people you know ("I know a lot of people who have done PhDs") these facts may indeed be true. But I would argue that it's not true elsewhere, such as in the US across scientific disciplines.
The research of Paula Stephan covers the economic decisions made by US science research institutions[1]. Her hypothesis is that academia maximizes PhD student numbers while the number of tenure-track faculty positions decline. This presents an untenable situation in the long term, where a flood of researchers with PhDs will be unable to find permanent employment, and yet the demand for cheap labor filled by PhD students intensifies.
As you can imagine, this type of trend can be terrifying to some PhD students, despite the "freedom" that their research allows. A lack of job security makes one question their salary as an extension of their worth.
Concerning the pay, I question what you call "little". Salaries in public research institutes in France may be little compared to what you could make at a good position in the industry and given your diplomas, but it's certainly not a bad salary in the sense that you can live off of it with reasonable comfort.