You know, alcohol, weed, and porn companies have managed just fine with user affirmations.
That the FTC would know there is no reasonable way would be a strong indicator it is indeed not a reasonable law. The default is definitely why Fortnite got fined, and is a reasonable reason to be fined, but it doesn’t make the law somehow effective it just makes Fortnite wrong for intentionally violating the law. I.e. they should have be fined but not because the law protects children effectively rather it’s not up to them to decide if it does on their own.
Changing the default will certainly reduce the number of kids who are subject to toxic game chat. FTC knows it, I know it, you know it, and Epic knows it.
perfect is the enemy of good here, the other poster is arguing that because it's not perfect and is easily circumvented that it will have no effect, and, as you said, we all know this isn't true.