There really isn't one in my opinion. Academic postdoc positions in many fields are pitched as a stepping stone to professorship, but professor positions are very few so you end up with PHDs continuing the low-pay grind after graduation to prop up academia for a dream that doesn't come true. I think it's good more are recognizing this and just going to industry, maybe eventually this will cause problems and academia can be motivated to fix itself instead of viewing post docs as disposable. Or maybe there's no problem to fix and this is academia just getting correctly recognized as the grind option for people who are actually ok with that

Postdocs are the single most productive members in a research group.

The PI is typically a tenured or tenure track professor, who got the job based on their research ability, but now they are relegated to an office, teaching 1-2 classes/semester, writing grants, reviewing papers for free for for-profit journals, reviewing grants for NIH/NSF, etc.

Grad students are not well motivated, not skilled, need lots of training, take classes, need to work on a thesis, and often times also teach. So they are low output and high time investment.

Postdocs require little-to-no time investment as they already have most prerequisite skills, have no other obligations beyond research, and sometimes even bring their own funding. They are basically professional researchers and are by far and away the most productive members of any given research group.

Much less experimental and fundamental research.

Companies aren't going to invest in experimental research in the biotech space as the costs are so high.

Most compounds end up getting validated in some way shape or form by researchers, then productionized by the private sector.

This has a pipeline effect on development in the industry.

For example, mRNA Vaccine research was purely experimental research done by postdocs and junior researchers at UPenn in the 1990s, before being commercialized by BioNtech and Moderna in the mid-2000s.