Except that's not really true, as most teams who have won a chip over the last 30 years went on to win multiple titles. Even if we ignore the 80s Celtics/Lakers/Pistons dominance, you get Bulls, Rockets, Spurs, Lakers, Heat, Warriors. The only non-dynastic teams (one-and-done let's say) were the 04 Pistons, 06 Heat, 08 Celtics, and 11 Mavericks, with the Heat and Celtics both having major superstars join an already established superstar to win a title. So if anything, it's easier to win multiple championships with the same core team than to move from one team and win again, wouldn't you say? The only other superstar that immediately comes to mind is Shaq winning with the Heat in 06, but I could be wrong here.
And you're completely missing the point regarding Kobe. But that's fine.