To me, Cap represents an ideal...something that you associate with Mom, Baseball, and Apple Pie. Thing is, we've changed a lot. We blame Mom for all our problems, Football has replaced Baseball, and how many people even bake a homemade apple pie any more?? (Some people might argue about Football replacing Baseball...but, a Sunday Night Football game beat out one of the final games of the World Series.) Face it, our heroes are mostly tarnished, and it's nice to have someone your kids can admire. (It's how I like my Spidey, too.)
Ultimate Cap is a nice What If? kind of Cap...but, in no way can he ever replace the ideal.