Game graphics are not really a thing for a small developer to have big exitement anymore.
There is no way to have comparable graphics to a Crysis or UnrealTournament (not more than just a one level
Tech Demo), as these Projects probably employ 20 Professionals over years for that.
Thrying to chase them will just end in frustration.

Graphics are more Fun on mobile devices for me. These Platforms have limitations as the computers back in the times.
Making a good looking game (comparable with professional teams) is possible for a small team still.
This will change in a few years probably, but not so quick either.

Artificial Intelligence will be in my opinion the biggest field to progress.
making an AI that can get there, and shoot that is not the problem anymore. But making
Characters that behave and talk like real People is still far off.
Also with the AI to communicate with the player, so that it feels like a smart Person is
still not evident yet.
Realism in graphics is almost reached. but realism on behavior of AI persons not.


In the end: game-creation is simply more commercial/professional than in the days mentioned.
So creating a full price game costs millions.
For millions you get 20 to 40 professionals (that make that for a living).
Thats the very simply reason why an indy/hobby developer can not get close to those game anymore.

Small casual games, internet and mobile games are still more accesable for them though.

The biggest! advantage for a non.professional tema is its freedom to create ideas.
Big commercial teams dont have such a freedom anymore, as their work has to get marketed.