Three words; Features_Replayability_Cost.
Sure, we could always have supplemental stuff for our same bucks in any shape or form... but,
1) if THE game we just bought has *more* features than every others tightly placed beside IT on the same store shelf
2) if THE game we now hold in our hands ready to go to the cashier has clearly written mentions on the box that we ALSO have editors, customization powers, moddable principles, etc
3) if THE game we're grabbing cash outa the wallet already having taken our tough decision is between 10 to 25% less than the next similarily valued (both in features & replayability factors) while we're on our ways to pay IT.
...then, what can stop any of us from enjoying it for what it is -- cuz, we clearly know what we're getting ourselves into?
I purchased X-Com:UFO Defense from the same set of 'practical reasons' as above. 15 years alter, it's still on Vista, runs smoothly in a Dos-Box -- because -- it's worth it. I can mod it, i can consult flawless reference guides & books about it, i can defy anyone into finding a more feature filled title (made ever since, btw), i can replay it all over again and be immersed indefinitely into its Tactical gameplay as much as i did when i first installed it from 3 floppies, etc.
Yep, it's Isometric, low res, oldy, Sci-Fi... but seriously, kick invading Alien butts from Earth, manage everything from production, financing, research, tanks, squads armed & gaining skills, intercept, shoot down UFOs, save civilians -- the list is long.
(PS; i could also add such titles as TotalAnnihilation, AoE and GC2 to that very short list of invaluable programming wonders... but none whatsoever compares to X-Com -- although, i'll admit to be biased towards specific strategy stuff while i simply hate FPS, RP, simulations ala-Sims, and other concepts)