&gt; total lock-in<p>You have these problems with carriers as well. They&#x27;re technically interoperable but they hit you with prohibitively expensive rates if you try to do anything international. Carriers are also effectively government-controlled monopolies or biopolies in a lot of places so users end up locked-in anyway.<p>&gt; lack of interoperability<p>Again, you have these problems. Yes, phones are interoperable with phones, but they&#x27;re not interoperable with anything else. IP-based messaging apps have the potential for phones to interoperate with computers, tablets, VR googles, smartwatches, and whatever else you want (although not all do at the moment -- Wechat and Whatsapp suck in particular -- but at least they have the potential, and some actually do interoperate with non-phone devices -- such as Facebook and Hangouts).<p>Phones may not necessarily be the center of everything 10 years down the road. I&#x27;d rather the freedom to innovate be with the software companies, not the operators of one particular infrastructure.