Cops want Apple, Google to kill stolen phones remotely – so why won't they?

As much as I would love thieves to lose access to stolen property, I'm not willing to give a kill switch to my property to these companies specifically and most companies in general.

Worse, in most jurisdictions that I am aware of it is perfectly possible to become the legal owner of stolen property and a company destroying that property due to theft would make them liable for the damage in those cases. In order to lawfully disable the device they would need a court order that proves that the person who currently possesses it doesn't do so lawfully... but that just means that the person who possesses it was (civilly) tried to not have lawful possession, so how did the court not order the device seized and returned? Why would you ever want to open that can of worms?

Then there are all the terrible revenge possibilities where an ex or whoever decides to report a phone as stolen. Again, either you know who has the device and can solve it civilly or you have no idea who has it and what the legal status is. The thief is criminally and civilly liable, but that might not be the person currently in possession.

Apple already allows the user to do this on their own, it's highly effective.

The government's position on this whole thing seems strangely like an unwise one trick pony that only works in specific cases / networks, unaware of other tech, and naive.

I understand that this is UK related, but why would we (particularly in the USA) allow cops to do anything "just because they wanted"?