The 727 is an old reliable gal but like old birds it requires more learning to fly her. Imagine trying to learn an L188 Electra now. The props alone are like 10+ days ground school.
I think trying to get through a 727 course requires a lot of work. A pumps on B pumps off,clear to push. Window heat, pitot heat, what's to eat.
The problem with IFL is trying to commute to the 727. IFL has limited CASS and rather difficult bases. They changed the schedule but the only ones willing to do that work and/or commute maybe less than desirables. Home basing would attract more but not too many left that want, or can, fly a 727 anymore.
Funny, as there are still a number of 727s operators and I know all of them have difficulty attracting/keeping guys/gals. It's one thing to fly it but imagine having to load/unload it and in YIP or worse, Canada, in the middle of winter.