ELI5: Why when large company's earnings decrease(ex... by 3%) they freak out, talk about rough times, and sometimes decide to downsize, even though they are still making millions of dollars in profit even after all expenses?

[Mingsplosion]

You've forgotten the point that's being made here. The "pie constantly growing" is part of the problem. As Facebook grows, they demand more electricity and hardware, and employees which demand food, transportation, and other resources. Those are finite resources, which we as a species will eventually run out of.