I think the genre has legs it's just gonna be up to another company to stretch those legs. FN laid the blueprint, someone else will have to finish the building. By that time the hype will level and BR games will be just another game until something new replaces it.
Low skill barrier and only one map means Fortnite is always going to be more limited than what the competition can put out, it'll still have appeal though being free. It's just benefitting heavily rn from being the only game on the market that doesn't run like shyt (looking at PUBG).
Eh, Fortnite having one map that is constantly getting smaller changes on a week to week basis is working. Introducing multiple maps could cut into queues, and the fast paced nature of Fortnite is only enhanced by the quick queue times. The game is pushing 1 year and it's still going very strong, and I don't think introducing more maps is what Epic should focus on. I don't know if more maps is how a game beats out Fortnite, especially when the game mechanics is what makes it dynamic more than anything else.