yes, what you're talking about is true for the supplier side, but it's still not accurate for A/C mfg. operators own the a/c and all the associated bits that would end up getting sent out for service, and they're the ones that are paying service fees to those OEM suppliers that supplied the A/C in the first place.
these day's there's not many "parts" outside of fuselage and flight IP that someone like Boeing/EMB, etc. owns that wasn't outsourced:engines, air data system, actuations, cabin, flight controls, landing gear, etc.. THere's nothing really that the A/C mfg could "service" to ever make back a 300mil airframe. the A/C sell for the fixed cost, sometimes the operator gets to select their own engine, but othewise they buy it for cash, not for future services. boeing and other A/Cs would not survive on maintenance plans because there's very little they actually maintain.