It’s like how every movie, even the rare no longer distributed ones are available on Torrent sites but you can’t find them even if you have access to a good online commercial libraries.
Let's not exaggerate here. I hit gaps in SH all the time. And I have to wonder how you haven't noticed that SH halted its 2021 paper uploads entirely because of the Indian court case. That's quite a gap.
More often than not, the reviewer requires additional checks and tone down some claims, so a paper preprinted as "we ended world famines" ends up as "our soy requires 5% less water than the second best".
What is infuriating is that Biorxiv is free and stores forever, but the final publisher gets more than $1,500 for the same service. And we have to do 98% of the edition (I've been required to change the font of a graph) so they can just feed your .docx into a program and it spits the Pdf ready.
100% false for other fields.