Universal implies more than just 50-50 split between sexes, imo. It's an impossible standard to reach for any consumer product
I.e. the FPS players could embody the military forces in a complex society where more RPG players are doing the diplomacy and strategy, others are playing in engaging "home front" social environments, someone is off doing city-planner/factory logistics stuff, etc. There could be some deep-diving, dungeon-crawling sub-games within all these realms, but also more casual modes too.
But, crucially, it is all tied together in a unified simulation so that these different player groups are actually steering a coherent story and state space for the shared world. The outcomes of diplomacy, warfare, industry, trade, local social groups, etc. should all have impact on each other.
To be honest, I'm mostly a solo FPS player. The immersive feedback loop is pretty much the whole draw. I would be open to a broader range of story/plot genres if they could provide this satisfaction. I don't need the "shoot" part of FPS, just the first-person part where my real-time, 3D movement and perspective gives me agency, objectives, and entertaining experience.
I naively imagined some game universe that could integrate multi-user input to adjust or build the story in a shared fashion. Like some kind of crowd-sourcing variant of a procedural generator. So your high level strategy would go through the filter of people like me trying to enact it.
But, I didn't really thinking about the real-time aspect of coupling user interactions. I wonder if there is some kind of statistical simulation model that could bridge these worlds with latency masking. I don't need a continuous 24x7 real-time simulation. I just need a coherent state model during my session and preferably some coherent story for how the sessions connect together...
I might have been thinking too literal with my examples. One could possibly make it work with some sort of averaging of people's play. I can't say what that might be like. I've not played online since Battlefield 2 except a bit of friendly Stellaris (which didn't go well).
A good strategist makes the outcomes of individual battles predictable. That makes it terrible for unit players.
I used to play Planetside 2 with a very organized group. Winning was fun at first but you were ultimately a cog in a well oiled machine so it got old fast. It probably got old even faster for the other players who were just trying to play a regular fps.