The issue with opting out is that with the exception of the Knicks and maybe the Heat, it is very unlikely Irving can get to any of his preferred teams while being properly paid. The Lakers, Clippers, Mavericks, and 76ers are already projected to be over the luxury tax, and a sign-and-trade for Irving would be complicated to execute since it would be difficult for them to construct the rest of the roster afterward. Any team that acquires a free agent via sign-and-trade gets hard-capped, and acquiring Irving would realistically put these teams way over the hard cap.