Why, thank you! They're an especially good deal if you collect them at the post-doc level, as you can acquire quality post-docs for right around federal poverty level wages, and then keep them on a trial basis as non-tenured faculty or research associates until they do something patentable.
Was this different in the past? In other words, are PhD students interested in academia knowingly entering a lottery system with well understood low odds in the hopes of eventually getting tenure? Or has the situation dramatically changed in the last 5-10 years?
Yes, it's changed in the last decade or so. Getting a permanent position as a Ph.D.-level scientist has been tough for a while, but it's much harder now for different reasons. First, the colleges and universities have moved to the adjunct model. They hire part-timers who get no benefits, and they save money. So this means there are fewer tenure-track positions available.
Second, complicating things is that the current tenure-track model evaluates two primary metrics: how much grant money you bring in, and how many publications you have in high-profile/elite journals. Funding levels are at historical lows (<20% of received applications) in most departments at the NIH and NSF. Some are
way below that level, as in, below 10%. In the 1970s and 80s, success rates were around a third or more. These days, the average age for getting your first R01 from the NIH (their most important grant) is 42,and the average age of all R01 holders is 51. Compare to 35 for first-timers in 1980, and probably younger than that before then. There's a nascent backlash against the elite journals forming these days. The argument is that they encourage irresponsible behavior and sensationalism.
A third problem is that we're turning out too many people with doctorates --- we tell them that there are lots of STEM jobs out there. Well --- there are if you want to be a technician. Not so many if you want to run a research group.
All this means that scientists get stuck on a postdoc treadmill. They work for low wages for many years (~$55K is the maximum NIH postdoc salary; $42K is the minimum) and have slim chances of getting a meaningful academic job. If they're lucky, they get a job in industry for decent pay. A lot of them end up doing technical writing or working in areas that don't truly require the level of education they have.
But the situation in science is better than the humanities, where there is effectively almost no chance of getting an academic job. At least technical writing at a biotech company is in your field. Humanities grads with doctorates often end up doing jobs that don't require their level of education. Some of them keep their doctorate off their resumes to avoid being labelled as overqualified for a job. Yet the schools encourage humanities undergrads to pursue doctorates, and they mislead them about job prospects. This is something of a scandal right now.