Personal data is by no means the only thing that makes users valuable for a platform.
The mere fact that they are there, that they watch ads and that they interact with other users (a small percentage of whom will pay as a result) would be of great economical value on its own.

> Paid users and monetized users are off-topic here.

The claim that "users are the product" is the closest to being true when we consider the main business model of these platforms: ads.
Advertisers aren't buying data, per se. Data can be use to target ads. But even if it weren't, the only reason advertisers join the platform is because many users, most of which are not paying, are there.
There isn't a product, there is a service. And the service is the ad space. But the (usually non-paying) user is the only thing that makes that space valuable to begin with.
And this stands true for other paid features that have nothing to do with advertisements.

> You can hide your IP on any platform. At least we agree that hiding your identity has nothing to do with the protocol.

Your IP is effectively the only thing you share by default if you use Nostr.
Do you know what you are sharing if you are using a proprietary app which connects to mainstream media?
How? You can only trust their claims. Your knowledge on this is no stronger than their honesty.

If you use Nostr you don't need to share anything which you aren't specifically trying to share, except your IP. You can more easily verify exactly what you are sharing.
The protocol is important because the fact that the protocol is open and simple is what allows you to use any client of your choice or even write your own.