As much as I'd like to see the Phantom cast to be changed up more often than it is (and as much as I resent the fact that they simply pulled McGillin back rather than looking for new blood), I really can't get annoyed about the cast's state of pseudo-paralysis without feeling like a selfish theatre brat.
First off, the actors themselves have been really quite good for a few years now, but more importantly, these people and their families have to eat. The reason people tend to stay with Phantom so long (and you still see OBC members like George Lee Andrews sticking with the longest-running show in Broadway history) is because it's easily the most stable production to be a part of. In the forever-and-a-half years it's been running it hasn't gone away and it likely won't for a good number of years. Unlike cast members of other long runs (i.e. Rent) and other shows that will easily become long runs (i.e. Wicked), Phantom cast members are typically older and have families to provide for. Many of them have said a number of times that Phantom put their kids through college. If they still want to perform in Phantom and it's best for their families to boot, more power to them. As long as the cast doesn't get stale (which luckily it hasn't been lately) I'll be happy if they stick with it as long as they want.
"If there is going to be a restoration fee, there should also be a Renaissance fee, a Middle Ages fee and a Dark Ages fee. Someone must have men in the back room making up names, euphemisms for profit."
(Emanuel Azenberg)