not always the case esspecially with shooters, i can pop in my cod4 and still get lobbies with a quickness, heck people even developed computer programs to set up so they could still play halo 2 together,
some people dont like moving on
now gears i never got into but im pretty sure you can just go to your nearest redbox and rent it for a dollar
CoD4 is a completely different beast than Gears though. Gears has stayed relatively consistent with it's weapons and play style. World at War, Black Ops and MW2 were all garbage compared to CoD4.