Shortages only occur at a given price, these paragraphs from your linked article encapsulate the issue:
"The cost of getting into flying is very expensive," Davis said. "When I talk to college students, if they're coming out of a four-year collegiate (aviation) program, most of them are $150,000 to $160,000 in debt. And that only gives them the qualifications to go be a flight instructor. If you're making $20,000 a year as a flight instructor you're lucky."
and this:
If U.S. airlines start hiring pilots in large numbers, he said, pilots now flying for foreign carriers will likely return home. There are currently about 90,000 airline pilots in the U.S. and Canada.
The regional's pay about the same as the instructor, see Michael Moore:
Michael Moore: Do You Want Airline Pilots to Be Working Two Jobs?
There is also the PBS story on the life of a regional pilot:
Flying Cheap.
If pay and conditions improved, this wouldn't even be an issue, high quality people would train as pilots.
There is no shortage, there is only a shortage at the price the companies are prepared to pay. Any shortage is entirely of an the airlines own making.