On the 34's being scarce. Those doggone John Wick movies. They've made finding a 34 nearly as bad as what Dirty Harry did to the S&W 29 back in the day.
Glock 35's can sometimes be found cheap enough that one can add a 9mm conversion barrel & be money ahead. Mine's working good.
Is that the reason? I didn't know that he carried one in the films.