This is one of the most interesting properties of peer-to-peer networks.
You can run your own ingestion algorithms, and one of the things you can do is set up inbound rules that incorporate micro transactions.
We have to build a lot of infrastructure to make this work, but it seems ideal for a world full of agents and autonomous systems acting on our behalf.
Do the outbound rules of other participants include microtransactions?
And who besides a spammer would pay more than $0 to have their message read by you? If I wrote a blog post about vulnerabilities of blockchains, or how I ran Doom on a pregnancy test, and you don't read it because I'm not paying you, you're losing value, not me. You guarantee an inbox of only spam — but at least you get paid for it.