You can argue all day about warrant-less wiretaps, but that's a red herring.
If the law should have power to discover data, denying them the power to do so via poor tools is a half-ass way to hamstring a policy that we agree is necessary.
Or we don't agree, and you want to bar the law from private information at any cost.
The reality is that police and federal law enforcement are able to acquire private information using other means including knocking on doors, physically bugging devices and people, hacking into devices and other ground work.
The law can have the power to discover data, but this power can be separate from compulsion statutes that force large corporations to surveil, store and copy customer data as a default.
What if there was a law that required you as a private citizen to spy on other private citizens? You would have to keep files on people, but you would only need to give them up if a search warrant or other court order was given to you. Wouldn't that be wrong? The only difference in this case is that Apple and Google and whomever else have filed to be incorporated.
Yes law enforcement should be able to access individual's data. No, it doesn't have to come in the form of a compulsory digital surveillance apparatus.
I really don't see how any of this is incompatible with the checks of warranted search.
Compulsory digital surveillance sucks, don't do it, but if it's required else the data is lost forever then it's required. (if you agree with the legal access to private data)
This is not complicated, you don't need to make it so.
What I think you are saying: it would be okay to force private citizens to keep tabs on each other so long as the warrant/subpoena and court system were trustworthy and in working order (i.e. in the case where there are very few abuses and mistakes by law enforcement).
(Also note that it isn't law _enforcement_ that we are talking about.)
Nor is it an intellectually void hypothetical. The Stasi did exactly this not so long ago.
Finally it appears this isn't what you meant in your post. What did you mean in your post?