@MatejLach They want what they can't have and have no actual right to: digital omniscience.
That kind of power belongs only to God.
Even if the state is unrealistically benevolent, any data the state captures can later be compromised by a clever third party with malicious intent for their own ends.
It will take time, but, eventually, I think this reality will bite the West hard enough that nation states will no longer want the legal and political risk associated with back doors and digital omniscience.