It's not as flimsy as all that. Put into plain terms, what is being said is
- previously, there were things that we could get out of the phone without breaking user encryption and we're happy to do so
- currently, those things are no longer available without breaking user encryption and in order to provide them, we have to fundamentally cripple our ability to provide user encryption, and we're not happy to do so
Something not talked about in all this is that had the FBI been even vaguely interested in the California ISIS couple BEFORE they pulled out guns, they could have had the keys to the kingdom whole, in real time, with all the metadata, text, voice and everything else. BUT since all that mass surveillance we've been performing is functionally useless, the FBI now wants to go back through and see what they missed the first time.
Which says a couple things: (1) all that mass surveillance you're worried about doesn't really matter because the government is so bad at it (2) Even when the government wants up in your business and have been given all the impetus in the world to do so, there's an extremely limited window of time (possibly none) during which they can go back and look at what they didn't already know.
This, your modern surveillance state, needs Apple's help to crack a dead terrorist's passcode - a terrorist whose wife posted jihadi sentiments on Facebook - from a country on the terror watch list - because they didn't have the foresight to monitor the terrorist and lack the technology to get the data once they've ignored it.