With the proposed 1$/yr/user it is going to take around 19 years to become profitable (with 1bn paid users). Facebook obviously wants a return earlier.
The founder did take those billions, so not sure what he was expecting to happen, ads looks like the only business model to turn profit quickly in this sort of business.
Besides, there are so many people using WhatsApp in developing countries that wouldn't pay if they can get something similar for free and competition in chat apps is big.
I never understand why ads and subscription fee needs to be an exclusive or for how the big players monetize.
I'd happily give Google $5/month for Gmail, $10/month for YouTube (I already do), $10/month for google search etc or $40/month for their complete package if they remove ads and respect privacy then. It's less than other "semi-essential" services I have to use like my ISP or car and if they make more than that of me from advertisements the advertising/marketing market must be bonkers.
The founder did take those billions, so not sure what he was expecting to happen, ads looks like the only business model to turn profit quickly in this sort of business.
Besides, there are so many people using WhatsApp in developing countries that wouldn't pay if they can get something similar for free and competition in chat apps is big.