Oh yeah because in reality, loaning a young, 3rd choice keeper has ever been successful for us (and most clubs).
City loaned out Angus Gunn, and got £15m for him based on one season of 1st team football. Good business that. Loans are equal part shop-window as they are development. Not every player you loan out is going to make it. Joel Pereira probably won't make it here, but he should bring in a reasonable fee based on his good loan spells.
The point is, the young keeper is going to want to have a career, playing football, here or elsewhere. A 36 year old goalkeeper has had a career. He's not wasting his development by training with us. A kid sitting behind two 1st team goalkeepers is a waste.
He also fills a spot for the homegrown quota, as Rob Green does at Chelsea and Richard Wright did at City. I think Wright was replaced with Scott Carson. Its common practice.