Yes, you can be happy with consumerism, if (1) you consistently have more and more money available, so you can continue to buy more and better things (see Kierun's link), and (2) you remain happy to continue working indefinitely to support your consumption habit.
The problem is that for most of us, one or both of those requirements fails at some point, or the whole exercise just gets old and starts to feel meaningless. And then where are you? If you have spent years -- or even decades -- building your entire identity and sense of purpose around buying new and better stuff, who are you when you can't do that any more, or it no longer brings you pleasure?
I would suggest some hard thinking/therapy about what it is about the act of spending money that makes you happy. Does it bring you a feeling of power? Or make you feel like you have succeded? Does it give you a sense of freedom? An escape from the drudgery of everyday life? The driver is the feeling; buying crap is just the tool you are using to achieve that feeling. So once you figure out the why, you can begin to investigate other ways to fill that need -- ways that may not give quite so much of an instantaneous high, but which leave you with a longer-lasting feeling of satisfaction.
