[notahacker]

But people almost invariably don't need BTC to transact with people they care about (the number of people with BTC denominated payment obligations is relatively small, and most stuff that can be bought with BTC can be bought with other methods). And as flawed as many exchanges may be, they make cryptocurrencies very interchangeable, especially compared with phones.

Blackberry actually did have a proprietary messaging system, it just wasn't anywhere near enough lockin because most people used Blackberry for other reasons, the non-proprietary messaging layers were actually better and Blackberry's popularity turned out to be nearly all down to being first in class.