One of the extra problems in the UK is that PhDs in STEM were massively centralised into “Doctoral Training Centers”. It used to be whenever I applied for a grant I would add funding for a PhD. Now that’s forbidden, and instead most universities have little PhD funding, and a few have far too much.

This means most students don’t get to be integrated into a research group, and many supervisors get very little funding for students as their university doesn’t have the funding.