That's a big if, though. I wouldn't pay $1/year for WhatsApp messaging as a consumer. But I have a lot of disposable income. When you have a free substitute, these signals get mixed up.
I live in South Africa and I'd pay $50 a year. Throw in a few paid-only features and I'd be quite happy.
All my friends use it. We use it at work for many teams. Video call with family in Australia. Audio with friends in Toronto or Chicago via Bluetooth while driving. That feels like magic. Better quality audio then the cellphone network and just works.
I have Skype, messenger, telegram, had Viber, tried WeChat. Barely use any. WhatsApp is like SMS, focused on my phone contacts, but has groups, audio, video, photos. That's all I want.
Here's an article discussing a local cell data bundle. It's still $1-3 per month. Poor people are willing to pay that because of the better value compared to SMS and voice call costs.
https://www.iol.co.za/business-report/technology/mtn-hikes-u...
Not being able to afford and not being willing to pay are separate.