No, Epic's problem is that they saw Roblox's success and went "we deserve that too because we say so, let's go all-in on this market that is already dominated by an established player!"

Roblox isn't killing Epic, Epic is killing itself by desperately trying to steal Roblox's players when they have no reason to stop playing Roblox. Even if they released a 50MB Fortnite client that streams low quality assets like Roblox, it would be no different because those kids would simply keep playing what everyone else is already playing. Tim Sweeney making another tweet about his metaverse or whatever isn't going to change that.