Yes, but the only problem with that is: as a non-invited one, you do not know how many were invited and who were not. So, you can't tell yourself, "Oh well, they only invited 5 people, no biggie, it wasn't personal." All you know, on our end of things, is that you (or, more accurately, your DC) was not invited. You don't know who else was and who wasn't. So you, in the absense of any other information, wonder why. Shrug. OH well.
Unfortunately, other than being discreet about invites (not handing them out in class or at practice, leaving them in cubbies) there's not much you can do about that. I am sure it is hard for a kid who was not invited to understand, because they probably don't fully grasp the concept that there are monetary and space limitations, and it isn't always possible to invite every child, even if you like them and their families just fine. Hopefully most parents can understand that, though.