The initial ideas for geostationary satellites dating back to their invention by Arthur C Clark envisioned basically manned space stations with communication en

The initial ideas for geostationary satellites dating back to their invention by Arthur C Clark envisioned basically manned space stations with communication enquipment attached. Only technological advances later on enabled the current ring of large independent satellite that are long lived yet still eventually expandable. Given that the GEO ring space is indeed finite & should be kept free of debris (even crossing one) at all costs I can imagine eventually reverting to the idea of large communication stations instead of individual satellites. The stations will likely still not be manned will support automated & possibly even manned servising. It could look likey large truss, kinda similar to the one used on the ISS. Inside it would host power & fuel interconnects. Attached to it would be the communication payloads, solar power modules, engines and fuel tanks. Periodically a resuply/repair craft would visit, replenishing fuel & swapping any failed modules. Depending on your launch costs broken mpdules would either be tossed to a safe graveyard orbit or brought back (possibly to a LEO space station) for refurbishment. The first steps of this might be already happening with the recently launched Mission Extension Vehicle: https://en.m.wikipedia.org/wiki/Mission_Extension_Vehicle https://en.m.wikipedia.org/wiki/Mission_Extension_Vehicle The MEV will grapple a satellite that is low on fuel and will act as it's replacement propulsion unit. In this way it can serve at multiple satellites and ppssibly even serve as a tug for satellites that have failed & are are likely to fail soon, to make sure they reach the designated graveyard orbit. And other similar & more ambitious missions are already planned and being built.