This is not just happening in games, but everywhere. The new generations break customs and traditions because it is their generation. All things fade except in the practices with high barriers of entry.
And the cost of developing modern games, specifically the visual elements, are acting as a reverse barrier of entry for the older generation of game makers.
It's just what time does to everything.
One day, when CG technology is advanced enough that any indie developer can create life-like top-tier quality visuals in their garage with consumer grade hardware, is the time when games will start to have variety again, and we shall see a return of many of the classical gaming concepts.