I will take a stab at describing how to achieve a global algorithmic feed.
First, let's acknowledge how weird it is that we cannot choose the algorithms that curate our feeds. Imagine that your phone came with a set of pre-installed apps made by a manufacturer, and you couldn't remove them or install any others. That is how phones used to work before Apple created the App Store.
Mobile apps are good analog to algorithmic feeds. The fact that people do not pay for curation algos today does not mean that they won't in the future. My money is on algo stores becoming an important piece of Nostr's ecosystem.
The marketplace could work in the following way:
  1. Algo designer submits his algorithm to the market & sets the price.
  2. The user chooses an algorithm and pays for it with lightning.
  3. The marketplace keeps track of user satisfaction from each algo, similar to the App Store's rating system.
  4. Algo designer shares part of the revenue with relay operators to ensure access to data.
Many users will likely prefer to watch ads instead of paying, and ad networks will also emerge over time. I suspect there will be something like Google AdSense, catering to algorithm designers, as AdSense caters to website owners. This way, individual algorithm designers would not need to run their ad networks to monetize with ads.