ESPN is ratings driven. They allow dissenting views if the views drive numbers up. Pierce just doesn't drive numbers up because he is pretty terrible as analyst and commentator and just isn't funny. He just can't pull that off like Barkley and Shaq, which is a large reason why TNT lets those 2 go off on tangents all of the time, and why ESPN reigned Pierce in.
I do wonder if Ainge wouldn't have been able to pull off the Allen trade (which led to KG), if he might have explored a trade with Dallas for Pierce. I assume Josh Howard would have been the main target along with some draft picks and probably Devin Harris. In 06-07 (so the year before), Howard just finished his 4th season and made the all star game for the first time at age 26. So theoretically he would have been a young all star just entering his prime. Injuries derailed his career soon after. Harris just finished year 3 and was 23 at the time and looking like he could be an excellent starting PG. He would end up making the 09 all star team scoring over 20 a game.
So Howard, Harris, salary filler (Dampier or Stackhouse would make the most sense), and a future 1st or 2 for Pierce and maybe a young guy like Allen or West
Boston obviously looks much different historically and certainly would have gone all in on rebuilding through the draft and around Jefferson. Who knows how that might have worked out long term.