Facebook do own Whatsapp, but if people are staying in Whatsapp then they're never engaging on the Facebook platform, and thus never generating ad revenue. It'

Facebook do own Whatsapp, but if people are staying in Whatsapp then they're never engaging on the Facebook platform, and thus never generating ad revenue. It's strictly a loss for Facebook, unless they can figure out how to monetize Whatsapp to the same extent as their main platform.