It starts with UK citizens buying iPhones and expecting their data to be private at all.
My comment applies just as much to the people working at Apple and Google as to the folks in the UK government.
It doesn't protect against every attack (eg. Stingray or evil maid) but it absolutely would protect you from a situation like the one in the OP. Breaking your encryption can only work if the OEM controls your phone more than you do.
I frankly don't expect the average Apple user to abandon their ecosystem, sunken costs and all that. But I do expect them to reconsider their unconditional support for a company that fights for the right to surveil them. LineageOS is hard to use, but as someone that already got most my apps off F-Droid it's honestly a cinch.
