There is nothing that stops tech firms doing exactly what they're being asked to do. Every claim otherwise is obfuscation because tech firms don't want to do it, mostly because of their internal internationalist politics where they don't want to be forced to pick sides and tell some governments "sorry, we're Anglos who choose to give the US/UK governments special access that you don't get because we're better than you". It's an example of the first kind of no, not the third kind.
End-to-end encryption is a vipers nest of false claims like this. There's lots of ways to implement such policies, like this: for each message that's being encrypted, you encrypt it under a per-message key which is then itself encrypted under the recipient's key, and also a police (public) key. The servers forward the messages to the police so they can decrypt them. If the decryption fails too often (hacked client) then that user is denied access to the network. Yes yes I know that WhatsApp/Signal and friends use a more complex protocol, that description is a simplified textbook example, but the argument doesn't change.
Cryptography is a very flexible set of tools. They can easily be used to achieve complex security goals, like empowering some parties whilst disempowering others. The resistance to doing this is legitimate and I even agree with it, but it's also political and not technological. When politicians push back and insist that their police should have access to WhatsApp, and get told it's impossible, well they are not all stupid and correctly conclude they're being bullshitted. Indeed some of the MPs in the UK have computer science degrees.
Fact is, buzzword salads can be used to baffle people and get them to agree with you even if you're wrong. Technologists are especially tempted to abuse them when they want to say "no" to make a Type 1 No seem like a Type 3 No. Researchers do the same thing all the time, your complaints about grant funding are as old as the hills. Honest specialists speak clearly even when they might benefit from speaking unclearly.