> the companies which use the service don't have enough revenue to contact their customers through dedicated channels. If you try to monetize this, then most companies just leave because those who could pay already have such channels to customers

I'm not sure that's true about the companies which use Whatsapp. They are not using Whatsapp because they can't afford anything else. They're using it because the clients use it. In a large part of the world, everyone uses Whatsapp for everything. Companies go out of their way to support clients via Whatsapp - they even pay for shady unofficial APIs implemented by third parties.

A company unable to afford "Whatsapp Business" probably doesn't need it anyway. They can just continue using regular Whatsapp. No need to force them to use the paid version.

Some of the use cases for Whatsapp Business:

- Customer service.

- Product listings.

- Orders and delivery.

- Knowledge base.

- Notifications (flight status, tickets, etc).

- Promotions.

A lot of these would be attractive for large companies.