FB has four massive "empires": FB, Messenger, Whatsapp, Instagram. They haven't monetized Whatsapp or Messenger much - maybe they never can, but for now that's potential opportunity. They have a strong grasp on their massive market share. They still have more monetizing to do on Instagram, which is already doing well financially. IG alone is worth more than Snapchat. FB has a lot of cash and keeps piling it on too. They were always profitable and raised a ton more than Snap, including the money they didn't lose by pricing the IPO at just the right price. Only hurt them for a short time.

FB has more immediate ways to expand too, most likely. We already saw them transition from relying on getting a cut of things like plugins and games in FB to that not mattering at all. They could try to go into payments more, maybe an Adsense alternative -- likely the only company capable of doing so too. Yahoo failed at doing it a decade ago and any other company has always been much more niche with much more worse payouts.