The problem here is... well, I'll make an analogy.
I have a safe. The government gets a warrant to search that safe, and since I refuse to help, they get a professional locksmith to open the safe for them.
Now, let's say I have a safe that the government can't figure out how to open without destroying its contents. In response, the government tells the safe manufacturer to start making different safes that the government can open.
Hopefully you see the problem with the second case.