Switching from bitcoin to litecoin seems trivial. I don't think the networking effects are that strong for bitcoin, especially since the current number of big users is pretty small. It seems like 99% of businesses who actually accept it are just using a payment processor, which could migrate to a new system overnight.

You can point to TCP/IP, but we've seen other protocols come and go. Back in the late 90/early 2000s's AOL messenger was dominate. Now nobody uses it. And that had very strong network effects, it was a messenger system.