Not only in the global south. Competition for smooth and fast user experience is such that most content providers at global scale own even the submarine fiber than runs from continent to continent, relay stations, landing stations, multi megawatt datacenters for in-country or regional distribution of content and the edge layer at the ISP level where based on you IP range they ship free the HW to proxy content and have it fast deployed to users at very low latency.
ISPs give free landlord services (they have no alternative) to this large content providers: rackspace, power, cooling and basic hw operation in exchange of barely cuting their carrier bandwidth costs.
IMHO, ISPs are key to develop Nostr at a higher scale, and instead of leaving them with crumbles on the table they should be running HW for Nostr the way that miners process the BTC transactions. I don't see any other model succeeding that won't include a seat in the table for ISPs.
ISPs need to be an ally to Nostr, since content distribution is a thing ISPs been doing all the work with continuous diminishing returns.