FB is too large an organization to survive long when competition is eating a huge chunk of their services. And especially so, if the competition is someone like telegram who is both free and open source.

Their decision to purchase WhatsApp turned out to be very ill-timed. WhatsApp was at the peak of their popularity when they did, but that peak was only because of ignorance of the masses - ignorance about glaring holes in WhatsApp security, and ignorance about significantly better alternatives like Telegram. But in the age of Internet, ignorance hardly lasts long among the masses, of all people, Zuckerburg should have known this!