I'm afraid that's not how the internet works. Very few ISPs have enough market power to demand paid peering from other networks. Comcast is one of them, but most others would be laughed out of the room for trying to pull a stunt like that.
> The ISPs bear none of the expense of "buying more IP transit".
Yes, they do. Very few ISPs are fully settlement free. Most use IP transit, public and private peering to interconnect with other networks. They may not need to buy more IP transit, but at the very least they will need to pay for the peering and transport infrastructure.
The alternative is obviously not to pay for anything and watch your interconnects saturate. Depending on how much of a (local) monopoly you have, this is either feasible, or not.
> That's always how the transit business has worked in the US -- the sender pays
That's not correct. To familiarize yourself with how transit works, refer to articles on Internet peering, IP transit and 95th percentile billing on Wikipedia. You can also learn some of the basics on DrPeering.
> this is how AWS works, and not by coincidence -- traffic within the AWS network is free in most cases, but leaving the network you pay
Amazon's billing model isn't really related to how IP transit and peering works. It's just how they set up their business.
> If you want to not pay, well, that's fine I guess. But nobody is going to take your traffic.
Plenty of people will take your traffic for free. Even gladly if you are on an Internet Exchange.
> And it's been this way since like 1990.
You've been out of the game for too long, if you think that's how things work.
> Edit: I'll note that it works differently in other places such as Europe because the telecoms are subsidized and partially owned by the government.
That's just factually incorrect. The willingness to peer has nothing to do with government ownership or being European. It's all about market power and what you can get away with. A prime example is Deutsche Telekom, who is notorious for not peering with (almost) anyone due to their strong market position in Germany. This and other similar examples poke holes in your theory.
Furthermore, the European telecoms have been privatized. The government may still own a piece, but they are not subsidized outside of normal universal service obligations.