I think the deciding factor is how important a particular campground will be to you. If the campground is not "all important", then you won't have much issue. If it is really important that you stay at "X campground", then it can be a much bigger issue.
For me, I pick the campground for the ambience and privacy and I don't want to have to end up in a "second choice" because of fit.
For others, they pick the campground where they fit and don't have a problem with it.
There's an area I frequent with about 8 campgrounds very close together. There is only one of those campgrounds I like and it won't take a 40ft rig. So for me, the size of the rig is important. For someone else, they might happily choose one of the 5 campgrounds that will fit their 40ft rig and be happy.
Only you can decide if that is important to you or not.