In my field (earth sciences), no. My grad school had unionized grad students, but that came in shortly before my time. I understand they got a lot of support from the faculty, which is a smile-maker.
Even without tenure, there is still a lot of agency in doing research.
If it's PI level most of the time you have to hustle for grants, which seem to go to less than a quarter of the proposals. At my school the profs had to partially fund themselves as well. Without tenure it's like being a modestly-paid consultant, with some benefits and much less alienation. Life can be so much worse. Plus you generally have the choice of bailing -- private sector PhDs can get six figures and still do related work (in weather/climate prediction).
That's without getting into oil companies, or being a quant. The employment prospects for MSs aren't as cushy of course, but then instructors, even undergrad, almost always have PhDs (from my experience). Of course, this was at places with strong grad programs.
So at least there's not much sense of being trapped, which probably has a lot to do with it.
That said, there is a concern for cultivating the field for the future that I still find disorienting after life in the private sector, and sense that the walls are closing in in a way that tracks the neolib project nicely (not that it is generally understood as such). I and others have noticed that in the older generation of profs, the ones without families are the exception -- that appears reversed in the younger generation of researchers, and usually there are identifiable reasons why they would be exceptions, like scoring tenure-track right out of the gate, and the previous good fortune that implies. Now everything has to go just right to make it all work the way it used to. I think there's some recognition of that.
-- Andy