To say I don't think of the overall costs wouldn't be honest. I/we do. The thing is though, is that we are fortunate enough to afford one. I don't really think too much about the costs of the unit and/or upkeep as I bought it knowing it is a sunk cost......I mostly think about fuel costs lately.
You can't take it with you, and if you still have enough to retire in comfort after all the toys, go for it. I will say that the sights we've seen, people we've met, let alone having our own amenities and moving on our own time tables makes it all that much more attractive.
When you finally reach the finish line of life, I think that you'll find that either way in the end cost a fairly large amount. It's what you get out of it that counts.