I chalk it up to the Knicks ownership being historically bad, for any sport (not to derail the discussion in that direction!) I don't think there's any way KD and Kyrie settle on the Nets if they're not in Brooklyn. Miami is clearly a destination even without LeBron: Hayward had it on his short list, and Butler just forced his way there even with the team looking really meh. LA is pretty clearly a destination for top stars.At the risk of futher derailing the thread, is there any evidence that NYC is in the "first tier" of destinations at this point either? We have Kyrie and Durant teaming up in Brooklyn this offseason, of course, but other than that we have...who, exactly? Amar'e Stoudemire? Granted a lot of that is due to the shittiness of Knicks' ownership, but that just goes to prove that factors other than just the locale are more important - it's not like players are looking at the Knicks and going "well I know their ownership sucks but NYC is such a great place to live I'll go there anyway."
Even LA and Miami - which I will grant you are definitely more attractive locales historically - really didn't become "destinations" in recent years until LeBron went there.
At the end of the day, Boston is probably in a tier with Dallas, Houston, Philly, Chicago, Golden State, and Phoenix: guys want to go there when it's well-run and the team has promise, but they aren't into creating teams there ex nihilo.