The government is a centralization of power, it doesn't matter if our devices are "decentralized" if the government can simply make it illegal to use unlocked devices. Or encryption. Or VPNs. Etc.
See also: "Let a hundred flowers bloom!"
That is a very binary view of the world, but the world is nothing but shades of gray.
At the very extreme of the most totalitarian government, you're right. Such a government can ban one thing or ban everything.
But in nearly every country, it's vastly easier to go choke a single neck (Apple) and tell them to shut something down, than to chase after tens of millions of individual people with individual devices, if all of them can run whatever they want from wherever they want.
That is the power of decentralization.