Sarcasm: I keep telling people that every video game could have just been Skyrim mods. Why do people even want to play other games?
If you want to play horror, sci-fi, mysteries, survival, cyberpunk, demi-god levels of power, etc., 5E is probably not well suited to what you're trying to accomplish.
I'll tell that to Ravenloft, Beyond the Barrier Peaks, Dark Sun, Eberron, AD&D, etc.
On a more serious side: I do favor other systems for other genres of RPG. I consider that quite a different thing than trying to run multiple different rule sets for similar fantasy storytelling.
GURPS is the system I prefer for my Westerns, Spy and Future (Aliens, Traveller or Gamma World) games. The non-heroic advancement in power is a better fit for those genres. I also prefer systems with primarily ranged combat to have a more robust ranged combat system than D&D.
However, I would not use it for fantasy. Why? The core GURPS magic system feels too 'Tolkien' to me with flashy parlor tricks instead of great magics. The combat is more specific in many ways, which doesn't facilitate high heroics and fantastical improvisation. So I am ok spending the time to know this additional system because it gives me something significantly distinct - despite not being able to run my D&D style games in it.
However, I have not spent the time to learn Pathfinder. I know it is a great system, but it doesn't do anything substantially different than D&D. Why would I want to learn it when I've invested so much in D&D? The answer is because I have friends that want to play it. They - for various reasons - some related to gameplay, some related to corporate politics - prefer a non-WOTC game. However, when they've invited me to play, I fake it and pick up a few things, but I do not have the level of knowledge in the rules there that I have for D&D, and because of that I make bad decisions in game. I am an A to A+ student of the rules for D&D, but a D student for Pathfinder. That has impacts.
What happens when our community splinters in 2024 between D&D, Daggerheart from Critical Role, MCDM from Colville, Tales of the Valiant / Black Flag from Kobold Press, and Pathfinder? Each has their fans. We're not likely to lose many more from D&D to Pathfinder, but there are many here that are more Critical Role fans than D&D fans. There are many that will prefer the stylings of MCDM or Tales of the Valiant. What that will lead to is different Game Masters running different games in different systems and a lot less rules knowledge at the table. That results in delays, chaos and frustation. For some groups: instead of a year to learn and really master one rule set we'll spend five years sampling several rule sets and not really mastering any of them.
We're better served by creating a single platform on which to tell fantasy RPG stories and then all capitalize upon it to build our businesses than to try to have the community learn new games for each game master.