The most startling figure from the article was that the number of Catholic priests today was the same as in 1950, I would have assumed there would have been less today. The only explanation for the constancy in numbers from then to now is that there were priests from the Baby Boom generation. That generation is getting older, the leading edge of it is approaching sixty. In twenty years, many of the Baby Boomer priests will either be retired or deceased. The ones ahead of them will pretty much be gone.
One big factor that this article ignores is family size. Yes, Catholics still have an average family size that is larger than non-Catholic Americans, but instead of having six or more kids, its been more like three or four. When you have a lot of kids, having one, two, or three of them going into Catholic religious vocations means you're not giving up a lot of grandchildren. It sure looks different today.
The sex abuse scandals have not helped parents encourage their sons to be priests. When you read horror stories from a few seminaries, you might be more reluctant to send your son to one. It's going to take a lot more housecleaning in that area before people become OK with sending their sons off to study for the priesthood.
One possible source of new priests is from overseas. I would imagine that the Catholic church can get visas for men from poorer countries whose families would be willing to send them off to be priests in America. This would be workable in Southeast Asia, South and Central America, and even Africa. I'd look for that to happen in increasing numbers in later years.
And its always possible that a future pope might allow married priests, or even women priests. It's not impossible, though it might freak out a lot of pre-Vatican II Catholics. Many of them are fairly elderly, so it might not be a problem ten, fifteen, or twenty years from now.