Even though Kobe has been in the league for 12 years, he's still only 30. There's still quite a few years left in him, and unfortunately for Wade, I think the conversation won't move away from Kobe vs LeBron until one of them retires. By then, we might be raving about some new talent that might be "the next Kobe" or "the next LeBron", or maybe someone else like Carmelo will be part of the next big "rivalry". As it is, while there is a bit of overlap between the SF and SG positions, Kobe and LeBron play different games, and comparisons are mostly for the sake of pitting #1 vs #2.
If you want to talk about what rivalries make more sense, I would argue that the best players who play the same position, i.e. Nash vs Paul vs Williams, or LeBron vs Carmelo, or Kobe vs Wade are more appropriate comparisons. Still, "more to be had" is a tough thing to pin down. In the end, #1 vs #2 will always capture the public imagination more than #2 vs #3, as well as sell more tickets and merchandise. At least from the league's and sponsors' points of view, isn't that what this is all about?