It seems to me that if the public can get together and form enough of a consensus to effectively regulate a standard via the government, that same consensus group should necessarily be large enough to persuade the cell phone manufacturers without resorting to force. After all, the cell phone manufacturers haven't initiated force against us, so we need no defense. They have simply attempted to sell the public phones. If the public doesn't want them, they should reject them.
You're right that this is ultimately a "proper role of government" situation, as all government policy must be. The government does not exist to coerce industry into producing a specific type of cell phone charger connector. To me, that is absurd. We cannot pretend to be free when our government holds such power over us as to dictate what we can and cannot produce.
The reason they don't do that is that there isn't sufficient consumer demand. The desire for standardized connectors remains held in a niche market. That's not to say that you can't get them. For example, there are many devices with Mini-USB support.
It's not so much that the government knows better, as that they have different priorities and the power to mandate that those priorities are respected.
The priority of cell phone manufacturers is to make money. When they can only obtain this money from their customers when their customers freely decide to give it to them, their priority must be to make products that their customers will buy. This is how the cell phone manufacturers are serving the demands of their customers.
I wonder- what priority of government are you referring to that is different than serving the demands of the public?