Microsoft has tried variety. They bought Minecraft, released Rare Replay, they're pushing Sea of Thieves, they had Project Spark. There's the usual suspects like Crackdown, Gears, Halo, Halo Wars, and Forza.
It's up to demand to drive their output. If the Xbox One is selling well (not better than the competition but well enough to be successful and profitable), then what's their incentive to change?
I like variety as much as the next guy. I don't really look at list wars. I buy what I like and I but whatever I want. I put my money where my mouth is. If M$ had Super RPG 6 and Sony didn't, that would be a good thing....if I actually bought Super RPG 6. A lot of people are more than happy to list games that they have no intention of playing.
I see 20 games announced for platform A but I only buy 7. I see 10 games for platform B and I only buy 7. At the end of the day, when it comes down to enjoyment, the numbers didn't really matter. As long as I'm pleased with what my platform had to offer, it's okay with me.
Then again, WiiU was my favorite platform for years so I may just be a crazy person. Please ignore me.
