> How would you feel if someone took ALL the books, repeatedly, and then sold them?
Books are rivalrous and excludable goods. If you take all the books, then others can't enjoy them. Open source software is non-rivalrous and (mostly) non-excludable. This is the thing that makes free software possible. And it's also the thing that makes it unlike the book example.
> decided to use one of my core open source libraries (which they haven't contributed to in any way) for a critical component of their commercial product, which also overlaps with my product's functionality in some ways.
This is really terrible, and I'm sorry to hear that it happened to you. But as far as I'm aware this has always been the whole point of "permissive" licenses. Licenses like MIT and (Berkeley) BSD subsidize the private sector with work done by the universities. The core idea, at least compared to GPL licenses, is to allow businesses to profit off of donated work. So while I sympathize with you, it seems like you deliberately chose a license that allowed and encouraged exactly the behavior you saw.
> And before someone says "why not AGPL?", it is because many companies don't touch AGPL software with a ten-foot pole.
This is presumably because businesses don't want to use software that creates in them obligations to give back. But you do want them to give back, or at least you don't want them to take too much. So I feel like there's a fundamental tension here. You're trying to make your project appealing to businesses by telling them they can take it for free and give nothing back. But you're also saying that behavior is "antisocial" and "completely destroys the offering/concept for everyone."