Good question. The proven model so far is reducing funding. Some universities found new ways to raise money by offering online and async course modalities. This benefits students who need the extra flexibility, and it's probably the most significant change that can be made. Increasing proliferation would require grants to surmount the initial investment and the need for guidance from the already successful institutions who paved the way.

Another change I'd like to see is shorter undergraduate programs. Most can stand to lose a few classes off the beginning that duplicate high school and a few off the end that duplicate grad school. That might have to be a political decision in response to the high cost of education. Shaving off a year could help you avoid the family issue entirely, especially if you worked for a year or two before returning to grad school.

Similarly, another proven model is that senior year of high school can also be used to reduce the duration of college. You can already get college credit, but it's a very fragmented and uneven system. State governments could fix that with policy, again to address the high cost of education.

I think the system is naturally starting to feel the pressure, albeit it took too long (and may have been expedited by COVID at that). Just look at the number of articles about a postdoc shortage that are cropping up in major journals within the last couple of years. The NIH recently had a "request for information" from late stage PhD students and early postdocs about what could improve their opinions about doing/staying in a postdoc. Anecdotally, many in biology are feeling the heat, and I've heard similar rumors in some other departments.

That said, I don't really trust the funding agencies and department heads to do the right things that will actually improve the long-term health of the system. I think we'll end up with a shitty band-aid solution instead like giving postdocs mediocre raises. It could take a really long time for the system to truly crumble enough to force change.

We'll see though, I hope things take a turn for the better in the coming years because certainly I know many PIs that are frustrated for one reason or another. If you get enough profs on the same page it could have some actual power.

What did PIs do before post-docs existed, and why can't they do it again?

Work.

They could, but why?