Eh.

The examples Doctorow user when coining the term were two sided markets, but if you actually read the original article for understanding, rather than to "well actually" on the internet, that the process being described is much more general than that, and is one of products or services becoming worse over time so that whatever value they provided becomes increasingly shifted toward shareholders.

This may seem weird in this case, still, because the only shareholder of Mozilla Corp is the Mozilla Foundation, but the principle still stands.

Moreover, you sound like a ridiculous pendant, because what's actually happening here is that Mozilla is turning Firefox into a vehicle for advertising, which means it's fucking entering a two-sided market... You're arguing that the sky isn't blue because it's night time at fucking sunrise.

Words mean whatever you want them to mean.

Is mozilla is showing ads, then it is a two-sided marketplace.

That's not the difference between this and the usual kind of enshittification. The users are one side, the advertisers (and google) are the other. Nothing unusual there. The difference is that this time it's driven by desperate grasping at straws, rather than barefaced greed.