[specialist]

Cool projects like money laundering (libra cryptocurrency), sex bots (PornVerse), and tree forts (data centers, office spaces) are about devs, not customers.

Facebook believes its core operational challenge is recruiting and retaining talent. That means buying their loyalty.

Separately...

Its financial challenge is preventing thieves from stealing its hard won cheddar. Such as governments imposing windfall taxes and thwarting its cash cows.

Its sovereign challenge is maintaining Zuck's continued dominion over the enterprise. Which will end shortly after Zuck, Inc's profits stop growing, causing a shareholder revolt. (And talent exodus.) I'm absolutely certain Zuck's financial team has predicted that crossover point with uncanny accuracy, including factoring the projections you identified, and much more.

I have zero basis for predicting that the status quo of Zuck, Inc will be stable for the next 5 years, and more likely 10.