This is only partially true. There are also countries like France where WhatsApp only has a Market share of about 22%. Switzerland is very split too, I personally know more people using signal or telegram than 'still using' WhatsApp.
Most people I know use WhatsApp (I refuse, and since I run Lineage OS without Google services I simply tell people my phone doesn't support it), Signal, or Telegram.
Reality is if you ask someone 'do you have whatsapp' or just message them a lot more than 22% will have WhatsApp in a way or another I guess. Buts it's not what they choose if someone asks which app they prefer.
Just as nearly everyone I know has telegram but I highly doubt it's their main way of communicating for most.