I'll put it this way: There wouldn't be a pilot shortage if the pay was right and regulators would stop putting in place roadblocks to professional airline pilot training like the asinine 1500 hour rule for first officers.
The saddest thing about this nation's corps of professional pilots is that it's a profession of people who absolutely love what they do and are exploited and treated as wage slaves by company brass who know this.
At this point, though, things are beginning to change in the USA. The airlines are faced with a glut of senior captains over 65 now and forced to take mandatory retirement. With typical starting salaries for regional FOs being about \$18-\$22k based upon a realistic calculation of pay, being on duty for 14-16 hours a day, and forced to live in crowded apartments with several other pilots, it's no wonder that people pursuing a career as a professional pilot have dwindled. This in contrast with the rising demand for pilots has created a situation where the airlines have no choice but to act. Salaries are being increased, and many airlines are adopting their own flight training programs where they cover the costs to train promising candidates in exchange for a mandatory employment contract for an agreed upon length of time (usually about 7 or so years).