Secondly, I will also point out that criminals in general watch whats happening to other criminals. If people start going to jail because there mobile communications are being targeted, others will catch on and stop using mobile tech altogether for criminal activities.. People copy what works successfully, you don't need to be smart to do that. So yeah this argument is complete bullshit.
Once the government starts mining data from iPhones, criminals will quickly adapt while every law-abiding citizen gets caught in the crossfire. It opens the door for abuse: officials could easily spy on their partners, dig up dirt on rivals, or target those they dislike without breaking any laws. Meanwhile, cybercriminals will have an easy target since every phone comes with this built-in vulnerability.
This system is likely to snag small-time offenders, not the real masterminds behind organized crime. This isn’t a smart solution for crime. It just sacrifices our privacy for a few token arrests.
Incidentally, as a non US and non UKer, my data with the major tech firms has no protection anyway. Welcome to the club, US citizens :)
You don't need a "vast majority" of criminals to break down a system and exfiltrate data when just a single, possibly state-backed, criminal operation can break your system down and do the job.
Although you're right that tech people would still be able to choose secure encrypted options, the fact is that the majority of criminals by pure numbers are not very sophisticated - so while this sort of backdoor obviously wouldn't be a guarantee that every criminal conversation could be snooped on, it would work on the 90-99% (I'd guess towards 99) who aren't both cautious enough to try to be secure and tech savvy enough to make the right choices.
(But it's still a terrible idea, both for the sake of general privacy principles, and for the risk that current or future governments or personnel will abuse the access, and for the risk that criminals outside government will be able to take advantage of the same backdoor.)