The latter.
The biggest fear comes from the US government compelling unwilling citizens to work very much against their own interests. If the FBI pulls this on Apple, there will be no end to jurisdictions demanding particular phones be cracked, and no end to jurisdictions demanding "back doors" be installed (lest Apple implement an "uncrackable" system) - all at Apple's expense, and to Apple's detriment as users can't trust the products to be secure. Also, the techniques & master keys will be leaked, either thru unintentional reveals (see the "TSA master key" fiasco), bribery (enormous black-market demand for such tools), or legal obligation (public record in court proceedings).
Given the two, I'd much rather a willing third party be contracted to crack the device in question. We know such efforts are underway (aforementioned black-market demand, among others) anyway. Apple would not be required to act against its own interests (imagine a bank vault manufacturer being required to hand out viable lock picks to bureaucrats). And the company doing the work does so in a fair & legal marketplace, lawfully disassembling of devices others built.
TL;DR - If Apple is compelled, they'll never be allowed to improve security beyond "back doors". If another company cracks the security, Apple remains free to make the next version harder (even impossible) to crack.