So they didn't actually change their names...they moved cities and adopted nicknames appropriate to those new locales...
Incidentally, the Houston Oilers were terrible, and the Baltimore Colts weren't good for a decade before moving. So as usual, do you have an actual point? You think pretty much all good teams keep their names for shits and giggles? Do you see teams like the Yankees, Lakers, Knicks, Red Wings, and Cowboys changing their names, regardless of how outdated those names have become?