Surely, as you get older (and tend to earn more via promotions etc), you don't have as much need to spend money because you'll have already bought most of the stuff you need previously?
You only need a replacement car every 5-10 years, you only need a bigger house when your family grows, you've already bought a mobile phone, ipad, laptop, HiFi unit, etc. You've already spent money on your hobbies so will already have the equipment etc you need to do it.
I certainly don't go around having more expensive holidays, or a new car every 2/3 years, or a bigger house, etc just because I can afford to. I'm happy with all the "gadgets" I have, happy with my equipment for hobbies, etc. Quite simply, I don't "need" to spend money on replacing/improving what I've bought previously. Happy going on the same kind of holidays I was going on 10/20 years ago.
Of course, it's optional, you "could" buy a bigger house, go on holidays to Australia, replace your VW car with a BWM, etc., but you don't "need" to, and can continue to have your life without. Whereas when you start out, you do NEED things like a home, car, etc etc.