-The Cowboys are called America's team because they have the biggest fan base. By far. Sure, they're probably the most hated too, but they definitely have the most fans.
-Signing TO didn't affect their fanbase. Why would it? By the way, you call him "unethical" - T.O. might be an asshole, but he is far far more ethical than many NFL players that get caught with drugs, steroids, breaking the law, etc.
-apex, I don't think T.O. will be gone next year. Jerry Jones loves him and the attention he brings the team. Plus, while he led the league in drops (with a detatched tendon in his finger & a broken hand in week 2), he also had 13 TDs (1st in the league), 85 receptions (18 20 yards or more), and 1180 yards. I highly doubt he'd going anywhere. If anything, Parcells/Zimmer could be gone, pending how the postseason goes.