20-Year Prospect
C'mon. This is an entry-level position in a massively popular organized religion that has outlasted at least a dozen apocalypse-level catastrophes from the fall of Rome to World War II. If there's job security to be had anywhere, it's within those sturdy walls.
The question is, will the nun and monk of the twenty-first century still be as relevant as those of the eleventh? In the digital age, religion and its role in life and society is being challenged and changed all over the globe. While a monk's life typically means he isn't surfing the web trolling on Reddit, sisters and brothers can and do use the internet for outreach and education (source).
And let's not forget that many monks have actual brothers and sisters (and nieces and nephews), so they might even have a Facebook page if for no other reason than to keep in touch. They probably still don't have an Instagram, though.