This might be true, but the history of telephone, SMS, email, and desktop messaging suggests otherwise. People don't seem to want a multi-faceted "platform", they simply want to communicate with other people.
For a while, xmpp was set to become this app, everyone on facebook, and everyone on google/gmail where on xmpp -- for me it was the first serious contender to sms. But neither facebook nor google/gmail wanted to federate, so while I could communicate with (almost) everyone I could sms via xmpp, it wasn't like that for most users (they used either facebook chat or gtalk).
Now google is killing xmpp in favour of hangouts, basically saying apple users can use ichat and sms, android users can use hangouts and sms -- so the only way to tell your friend (as in any of your friends, using one app) you're late for a meeting is sms (still/again).
Unless Google and Apple (owners of Android and iOS) get their shit together and accept that federated xmpp is actually pretty f*ing useful I see nothing but fragmentation in our near future.
The only possible light in the end of the tunnel is the death of telecom and birth of datacom, with everyone moving to SIP (or equivalent) with cross-platform, cross-provider presence-notification, voice, video and text communication.
In the mean time these toy technology companies can play with their stock value, but I really doubt (and really, really hope) none of them will "win", where winning means reaching the global status that PSTN/regular voice phone and sms has today.
I think anyone that thinks differently need to wake up from their dream.
[edit: forgot 1]: data transfer costs money, and will continue to cost money. But you won't be paying 20 cents to send a short message, you'll be paying by the gigabyte, as you should. With all income from voice and sms falling away, I'm not sure what will happen to gsm/lte style wireless prices, I'm guessing there'll be similar tiers as today: ridiculously expensive pay-as-you-go (20 cents a megabyte?) and whatever-people-will-pay monthly (flat-ish) charges (in Norway that'd be around 50USD/Month give-or-take).
> Want to shop for shoes with your friends now?
No, I definitely don't want to go shoe shopping with my friends in an SMS app.
0: http://blog.codinghorror.com/has-joel-spolsky-jumped-the-sha...
It even has the same very low barrier to entry - You don't need to explicitly add contacts, it takes everything directly from your address book, which is likely already full of your friends/people you know. Hell, you don't even need to create a new account, it validate automatically your phone number with an sms. While this is awful privacy-wise, and kill the possibility of an easy-to-setup desktop client, it makes everything really easy for everyone, especially those that use their smarthphones for most of their online tasks (which seems to be a big group growing every year).
Nothing more, nothing less.
In this sense, LINE etc aren't so much like FB or other "giant ball of mud" social apps, and present a much bigger threat to whatsapp.