What’s acceptable?

I am a studio member at a local pottery studio. They offer a lot of classes and have a dozen or so studio members. However, they are always behind on firing. I do throw bigger bowls (10”-14” diameter) but I find myself waiting 45-60+ days for glazed pieces to be fired (which leads me to hold off on glazing new pieces before I see how a combo turns out). Bisque firing is usually 20-30 day turn around. When I say something to the owners, they make excuses or laugh it off. What is an acceptable amount of time to wait for pieces to be fired? Thanks for any input!