It's the latest iteration of "a little X is good, a lot of X is bad".

Email was awesome when it first became widespread. I could cold-email random professors at other universities (I was in school at the time) and get meaningful responses back. Then lots of people (and companies) started cold-emailing, and it stopped working.

Social media is broken if there's nobody there, is great with a medium-sized community, and is broken if everyone is there.

Ad-supported websites can offer all kinds of valuable free services. Up until either (1) they become so ad-infested that they're no longer useful, or (2) all the users block ads.

There was a wave of websites providing APIs for programmatic access a while back. You could script together whatever flow you wanted. If no API was offered, you could scrape the HTML. That triggered a wave of alternate interfaces to sites, skipping their ads, skipping their engagement funnels, separating the value from the cost. So everything got locked up behind captchas and accounts and API keys with limited access.

This outcome was always inevitable. Humans don't understand social contracts, or they do and both sides abuse the hell out of it. We feel entitled to have just the loss leaders without ever buying anything else. When running businesses, we feel entitled to keep adding more and more adds and generally enshittifying the experience. People can take it or leave it, after all.

Agents don't change the underlying structure at all. They just magnify and accelerate parts of the system, and will therefore magnify and accelerate the reactive and defensive responses.