Well, when you have grant money for a project on X most supervisors will not let you do Y. Most students wouldn’t do research on Y if they weren’t going to be funded. I work in a lab where everyone else has to play ball by their grant proposals and you can sense a general lack of genuine curiosity. Which makes sense, they are not really different than a contract employee with a very specific deliverable that was designed before they even showed up. I can’t speak for other fields but especially in biomedical/compsci where your peers are making six figures working for graduate pay for 2 years (MSc) and then another 4-6 (PhD) doesn’t motivate you to engage outside of your exact degree requirements and your project. Add on that “curious” research doesn’t have a guaranteed path to publishing or to success and it suddenly becomes less appealing to gamble your future on such a thing. I would label my own research as “curious” in that I have support from professors at a few universities but on the whole we are facing challenges from academia at large. The only reason I can comfortably pursue something that has a genuine non-zero chance of failing into obscurity is that I am funded by an in-house university scholarship and I have a full time job.