I believe that Cavs are very serious about winning, it's just that for the most part, the big moves they did make were flops. A year after being an All Star caliber player, Larry Hughes fell back to Earth and became Larry Hughes again after getting a fat contract. They gave Z a huge extension for about 10 mil a year or so, I don't think I need to explain why that was a mistake. Then they made a big mid season trade for a declining Ben Wallace. The Shaq trade was a complete disaster which didn't surprise me at all. The Jamison trade didn't work out which did surprise me. So they did try to make moves, they just didn't work. I can't fault their effort, but they were unable to find a legit #2 guy to run beside Lebron. Unfortunately for the Cavs, they couldn't pull a Kwame Brown for Pau Gasol.
With that said, Dan Gilbert revealed himself as a jerk. There is nothing wrong with the decision Lebron made. Everyone says they don't like the NBA cuz the players only care about money and not enough about winning. Well he's taking less money and went to a team with a better chance to win. The way he made this into a big circus is another debate.