If Apple continues to resist, the FBI will simply take the source code and signing keys and hand them over to some contractor to do the work. Is that better? Apple's source code and signing keys in the FBI's hands?
It would be better to push the FBI into that position, yes. Make them steal that property at gun point, literally. Force them to show up at Apple HQ, with SWAT teams, threatening to murder innocent, unarmed engineers in the streets. Make sure every news source available is there to witness and broadcast it live. Why force it? To drop all pretext of what this really is, and reveal the US Government's actions as being…
Or a single election. Hitler gained initial power democratically, after all.