The fact that ED's DCS modules are getting more and more complex is great, but also problematic in terms of time spent learning all systems effectively. So yeah, I agree with OP.
I could happily limit myself to only flying the F-18, F-16, Jeff, and the future Eurofighter, while stopping to purchase any other module that I will likely never get into (I prefer modern jets).
However, I won't do that and will continue to buy every flyable DCS module and any new terrain that's coming out, just to keep everyone going - and thus sustaining my beloved DCS hobby as well.
As a side note, as modern DCS modules tend to get more and more complex, and I really wish there was a lot more hand-holding via built-in training missions to teach us all those systems from the ground up (not talking about videos online, but actual training missions).