IT gets a ton of respect. He's the best offensive player in NBA history under 6' (unless Iverson was really under 6'), he's earned a great reputation as a player and teammate, and he'll have earned himself a great payday after this season. He has a legit shot (probably better than Kyrie) at an NBA championship this season and there was a great chance that he would not have returned to Boston after this season as Boston probably would not have paid the max for him. IT was complicit in his Boson departure. He clearly a promoted himself as the "King in the 4th" (the look at the watch in the 4th gave him notoriety while his consistent performance cemented it) and he was crystal clear that he want someone to "back up the Brinks Truck". If IT was planning to take a hometown discount, he sure wasn't making it appear that way.
IT has been lauded by the C's ownership, management, former teammates and fans for his efforts. BUT... he is not Kyrie Irving, just as KI is not Lebron James. Forsberg is saying "Isaiah Who?" just indicates the truth -- that after 20 games, the C's do not miss Isaiah Thomas on the court. This doesn't mean he wasn't loved and doesn't mean he wasn't highly respected for his accomplishments here.
And as a result of those accomplishments someone will indeed back up the Brinks Truck.