Brewing, like most, if not all hobbies, loses its luster after awhile. You start out, and think it is the coolest thing ever. You get a few batches under your belt, do a bunch of research, get your processes down, and pretty soon the mystery is gone, along with the novelty of it. At least that is how it went for me. I still brew, and still enjoy it, but I no longer LIVE for it. But there always seems to be something that renews my interest and keeps me brewing. First was going all-grain. Then a kegging set-up. Then I learned to re-use yeast and I built a brewstand. This year I am going to plant hops- that has me stoked again. Plus there is now a homebrew club near me, so I have met lots of new brew-minded people. And my new GF completely supports my hobby, and even likes some of my beer.
I guess all I am saying is I completely understand how brewing can lose its luster and its mystery, but at the same time new things keep popping up to keep me interested, too. I have been brewing since my oldest son was born. He is almost 15 now.