Star Fox games came out in 1993, 1997, 2002, 2005, and 2006. Longest gap was 5 years, when they tried something crazy different (Star Fox Adventures). We'll see one in 2011 at the latest. Maybe they're trying something crazy different, like motion controls.
Besides, Brawl had 3 characters from Star Fox in it. Nintendo loves the series. The last 3 Nintendo consoles each got one Mario, at least one Zelda, and at least one Star Fox. It's the Nintendo way. We all just have to believe in it hard enough to make sure it happens.