Don't be fooled by the fact Milwaukee has a Major League Basebal team - it isn't a major league market, If the commisioner wasn't the owner it's a AAA town. And while UW is a legendary NCAA program, the Milwaukee area isn't really a rich, thriving hockey hotbed. It should be - no reason not to be like Minnesota, New England and Michigan on that score, but it just isn't. Hockey is a definite afterthought in Wisconsin's biggest city, and the other cities are too small to balance that off.
And no, Green Bay works for football because attending a football game is a major nearly full-weekend event. Hockey needs to be somewhere you can get home from after on a weeknight. It's Milwaukee or nothing if you're talking about Wisconsin, and Milwaukee doesn't, in my opinion, have the quantity of population and business to pull that off without a very-heightened specific interest in ice hockey - which the city lacks.