What about business features? Pretty much every business in my country advertises a Whatsapp number, from large companies to mom-and-pops. People contact them over Whatsapp to ask questions, make complaints, order stuff, everything. I can't believe Facebook is unable to monetize that.
It seems to me that Facebook is severely biased towards ads because they already have a platform and it's a market they obviously know well. That doesn't mean ads are the only way to make money.