a few thoughts:
-it will be difficult to attract a max deal type player, as this team stinks and has no direction. recent history suggests that a max deal player tends to go to a team that is established and/or on the cusp of being a contender.
-a lot of players in this generation do not care about celtic tradition and folklore. to this generation, celtic pride and tradition is about the recent big 3 era and the bird era. for many, being part of celtic history will not impact their decision.
-many max deal type players want to market their brand. destinations rooted in entertainment beyond basketball attracts them
-many of the franchises in the nba are cold climate cities in the winter. i dont think the weather necessarily is a major factor in attracting free agents (i think for many players, $ trumps weather), however for some players, being in a warm climate is more attractive.
-although it might not be accurate, their is a notion with some, that boston remains a racist and/or racially insensitive city. boston has progressed leaps and bounds, but for some nationally, it is not a community they wish not to be a part of.