I have bad memory in general, but of this in particular, I'm very sure. Because I remember that some people actually switched to Telegram upon receiving the message saying they had to pay before some deadline or they would lose access to WhatsApp, and I thought "at least this is a silver lining, some people are switching to Telegram".

I also distinctly remember that I didn't pay by the deadline (although I planned to cave in later) but finally the threat didn't materialize and I didn't lose access (or maybe I did, but for a day or two). Some people did pay and didn't get any advantage over those of us who didn't.

This was in Spain, so maybe the issue is that the specifics vary per country. In particular, I think your point 1 wasn't really true here. WhatsApp monopolized messaging (including even elderly population) because it was free. You wouldn't convince most people here (and especially the elderly) to pay for an app, it would be dead on arrival. Perhaps the charge after the first year you mention was somewhere in the official small print, I don't know, but I'm pretty sure everyone was using it under the assumption that it was free. They only tried charging a fee that single time I'm mentioning, and they backtracked fast.

It's definitely not unlikely because I very clearly remember WhatsApp being a paid app from the beginning, but I also remember no one actually having to pay for it. Couldn't tell you how exactly it worked but I've used it since I was a kid to talk to my friends and family, while we didn't even know how to do online payments.