> the service that Facebook provides is unparalleled
Except that it's not. The vast majority of what Facebook does can be done without Facebook. The essential problem now is that there are large numbers of people who have only ever known Facebook and are unaware of how to accomplish those things without it.
"Can be done" without Facebook and "Is possible now" without Facebook is two separate things. It would take billions of dollars to create the network effect FB has now, which is the moat any other network would have to cross.
Except that it's not. The vast majority of what Facebook does can be done without Facebook. The essential problem now is that there are large numbers of people who have only ever known Facebook and are unaware of how to accomplish those things without it.