There’s nothing stopping governments from banning E2EE, but in the absence of such bans, no one is under any obligation to build systems that empower them to spy on their users.
I wouldn’t be sure about that, the phone companies already have a legal obligation to allow wiretapping and the government is very happy to put gag orders on this stuff.
Shouldn't the E2EE apple walled-garden app equivalent of wiretapping be pushing an app update to the suspect's phone with a sidechannel added for law enforcement to snoop, with warrant in hand?
CALEA has a carve out for encryption. I’m sure when E2EE is about to be deployed to the masses the law will be updated to force key escrow.