I'd say more than 99.9% of WhatsApp users haven't heard of Telegram.

WhatsApp users are mostly not early adopters like you and your friends. They are ordinary people, because WhatsApp is is a simple communication tool targeted to everyone. And that's why they keep doubling their user base.

Unless Facebook actually puts their logo on WhatsApp, hardly anyone would notice. The tech community is minuscule compared to the large number of non-tech people using WhatsApp.

The uproar in Spain about WhatsApp switching to $1 per year was huge, noisy and... emphemeral. Line got a lot of new signups for a few weeks, but the only person I know that still considers using Line today didn't even have WhatsApp back then (but, like everyone else, does have it now).

Unless everybody switches, few will switch. Network effects also create some pretty powerful stickiness.