What's to stop a free alternative like Telegram taking all the market? Smartphone adoption is still happening here, and I use the rates are much lower in developing countries. Once word gets around maybe everyone will switch.
The key though is that Telegram actually isn't free to consumers when compared to Whatsapp. At $1/year + access to everyone who is already on network vs. $0/year + access to smaller network+need to invite your friends to build that network Whatsapp is actually (significantly) cheaper. If it was more expensive per year I think they'd be giving some room, but no one is even going to notice getting billed.
