This is a really unfair comparison imo. Second Life is all about expressing yourself. And you’re not buying Linden Labs approved corpo collaboration bullshit feat. DJ Music. You’re buying stuff someone else made, and they get paid for that. You build a character that is a digital representation of your inner self.
In Fortnite you buy a skin which is just the current hot flavor of the month. But also: It’s a action game. The goal is to shoot other people, meaning that you obviously do not spend any significant amount of time looking at yourself. And when you look at others, you do not admire their skin, you use your neurons for tracking them.
But also also: Every skin is the same. So when you come across Hatsune Miku, it will always be the same one. These skins aren’t a representation of you, they only signal that you like whatever media they were collaborating with at the time and had $20 lying around you didn’t need.

Naww give me Second Life all day any day.