The older fleets are grossly overstaffed and the reason is because of poor planning by the back office in terms of what to offer in class. Hundreds of pilots have been sent to the 145 and a few to the CRJ, with no operational need for them, leading to massive reserve lists and 30+ pilots per base sitting around every day flying less than 10 hours a month. For some reason, they are very wary of over-staffing the 175, and do not spread pilots around proportionately to anticipated need/attrition.

Permanent FO seat lock prevents this situation from resolving itself naturally, making the bad planning even more obvious.