You ignored the second half of that sentence:

> syncing data between computers you owned that all had publicly routable addresses is a much simpler problem.

In no way am I denying that people would like to solve the same problems easily. What I'm saying is that it would have been a much simpler problem requiring much less infrastructure. An application like SyncThing that works without any central infrastructure would have been an order of magnitude easier to implement in a world where every internet connected device had a unique routable address.