After using it for a few days and having an account for a few hours (this is my first comment), I don't think it will ever directly compete. But I think it does have chance to represent a "significant minority" of internet traffic if it doesn't peter out early on, and it may already be passed the threshold for that happening.
You'd never say email can "compete" with twitter, but it's still a significant way people interact with the internet. If lemmy does for independent communities and niche forums what email does for messaging, I'd consider it a huge success!
This game is actually a bit before my time since it was released two years before I was born, but the original XCOM game (aka UFO: Enemy Unknown) is still one of my favorite games of all time. And it's just gotten better over the years with fixes and modding through OpenXcom.
I like the modern Firaxis games a lot too, and Xenonauts even moreso, but nothing has quite hit the same as the OG.