If the company wants a mandatory retirement age, their best avenue is to approach all those Congressmen and Senators that Uncle Warren has in his pockets like so many nickels and dimes. They can drive a regulatory change within Part 135/91K to harmonize with Part 121. One level of safety, right?
As a top 500, large cabin PIC with little more than a decade til age 65, I would WELCOME mandatory retirement. It SLAYS me how the usual suspects within the union can defend the fact that we have more than 220 pilots over the age of 65 including NINE over the age of SEVENTY-FIVE!!?!??!!???