Is there a shortage of pilot applicants for the major pax and cargo airlines? No.
Is there a shortage of pilot applicants for the LCCs (Spirit, Allegiant, JB, SWA, etc)? No.
Is there a shortage of pilot applicants for well-regarded Pt 135 and Pt 91 operators? No.
Is there a shortage of pilot applicants for the regionals? I guess it depends on the regional, and it also depends on how you define 'shortage'. Skywest, for example, is having no trouble filling classes. When I interviewed with 6 other guys, only 2 of us received offers. The 4 other guys all had clean records, relatively high time for regional applicants (avg. 3,500 hours), and a good mix of experience. So I'd say that it doesn't appear that OO is hurting for applicants, given that they don't seem to have lowered their standards one bit.
Neither does it seem that Horizon or Compass are hurting. That may not be the case at other regionals...a buddy of mine interviewed recently at SKW and actually was collared by a Mesa recruiter in the Candlewood parking lot as he headed to the shuttle to his SKW interview (I thought that was an urban legend until it happened to a guy I know.)
I think the reality is that there are thousands of seasoned ATPs with significant amounts of flight time who are currently employed in non-aviation fields, but who would return to the 121 world if the pay was better at the regionals.
So is this a pilot shortage? I don't think so. I think what we're seeing is that instead of 10 applicants for every 1 FO slot, there might be 5 applicants for every 1 FO slot.
Then again, I'm not a recruiter for any airline, so I don't live and breathe that world. So my post is worth only what you paid for it