You can chose not to ever fly on an airplane. According to the logic above, it's just a convenience. Nevertheless, people generally don't dismiss issues with air travel by saying that you can just chose to drive.
In reality, a lot of the systems you think are essential to your day-to-day life are technically opt-in. Except you cannot opt-out without cutting yourself off from the society.
Also, societies are not established by armies. They are established by social conventions with enough clout to become self-sustaining.
The Internet was originally established in a way that was very different from the current version of an offline society with its hyper-centralization and authorities. But the consolidation of services and infrastructure significantly changed that model.
>What Facebook and Google have is massive, large scale user loyalty.
Google has effective control of web standards.
Edit: Also, the podcast directly addresses your comment. In fact, that's what it is about.