> First, if academics wanted to work on topics mandated by somebody else, they would go work in industry for that somebody, and earn much more money than they earn right now.
Very few academics become principle investigators. Most every academic who's not a PI is working on something for that PI.
The vast majority of those working for a PI are students and postdocs, which are inherently trainee positions. Though, depending on the field and the PI, trainees may also have plenty of freedom to work on their own topics. If you want an actual career in the academia, the main options are becoming a PI or choosing a teaching-focused position. There are some staff scientists and similar, but such positions are rarer than tenured professors.
Do we live on the same planet? I understand that the point of being an academic is to always be learning, but there's no place on earth I know of that thinks of someone with a PhD as a trainee.
> the main options are becoming a PI or choosing a teaching-focused position. There are some staff scientists and similar, but such positions are rarer than tenured professors.
Implying that one gets a choice is bold. My understanding is that there's a job for about 1 in 10 postdocs in academia these days.
A postdoc is a training position, where the individual further develops their skills and tries to build an independent profile while being mentored by a more senior academic. PhDs who work in someone else's projects without focusing as much on personal development typically have other job titles, such as project scientist or staff scientist.
Receiving a doctorate does not mean that you have finished your training. Some countries have habilitations or higher doctorates, which can be understood as more formal versions of postdoctoral training. Medical doctors are expected to specialize and receive more training as residents. Other fields have similar arrangements, some more and others less formal. If a full career is 50 years and the job requires a high degree of specialization, it can make sense to use the first ~15 years for training.
The number of academics who achieve a 50 year career is vanishingly small. I can think of a handful I met in a decade. To call the other 99.9% of academia in-training is a bit of a mis-nomer, whether it's the accepted terminology or not. That was my point.
And my point was that academics whose primary job is doing research in someone else's project are even rarer than tenured professors in research universities.
A postdoc is primarily a career advancement position rather than something where you are expected to contribute full time. Such positions are also pretty rare. There are something like 70k postdocs in the US, vs. almost 190k tenured or tenure-track full-time faculty in research universities.
It's true that serial postdocs exist (though schools tend to have term limits and even limits on years since PhD on postdocs), but it is certainly intended to be a trainee role. Even postdocs with fancy fellowships generally have sponsors.
Sure, but PhD students are still working on topics that they (at least partially) choose. As a PhD student in the USA, you have choice over your advisor, and hence choice over your research niche. Within that niche, you don't necessarily have full control over your project, but it is in everyone's interest to align the project with the student's interests; nobody wants a project that was half-assed because the student hated working on it.
Very few academics become principle investigators. Most every academic who's not a PI is working on something for that PI.