That's been my experience. At some point during a generation, I always buy the second console, and I always end up regretting it, because I don't find any real use for it. I suppose I get drawn into feeling like I must have what the people on the other side of the aisle are talking so enthusiastically about; I must have it for myself. However, when I get it, I'm invariably underwhelmed, and it ends up mostly unused. After about 6 to 12 months, I get tired of looking at it -- it seems redundant -- and so I sell it back, at a loss.
Different people have different gaming needs and tastes, of course, so YMMV. I've learned that I'm a console monogamist, though -- a one-console gamer. One console gives me more than enough to choose from. A second feels like too much for me. I've gotten increasingly less interested in gaming as the years go on, too (e.g., haven't played a game in the past month), so that's a factor, too -- someone who is more "into" gaming might really like having two consoles.
