FB has had solid revenue and net income for many years, so much that it’s one of the most valuable companies in the world. It’s not comparable to MySpace, and definitely isn’t going anywhere anytime soon.
Facebook could very well be an outlier. If it isn't, it could definitely go away in the coming years.
In any case, that shows that its revenue/income is not a predictor of anything. When a company spirals down, it does so at an accelerating rate and can quickly burn through any amount of cash.