Marvel’s quality has been in freefall since before Endgame came out, and most people lost interest after the payoff. Their shows are terrible, and the last movie was so bad that even critics are lambasting it.
DC’s cinematic universe has been a clusterfuck from the get-go, and although they still make epic animated films their live action movies are rarely worth watching.
Hollywood has been blaming super hero fatigue- claiming that the genre is overdone and will go the way of Westerns.
The fact that people are still interested in Invincible proves that the genre isn’t dead, it is just full of shitty films and shows that nobody wants to watch.
I mean most of the hype for this show has been from people who liked the show and also Fortnite so I don’t know if it’s a super good comparison. DC’s movies are also just so sucky I don’t want to compare them to anything else.