I wouldn't specifically limit this to just Howard, but, I do agree with the sentiment of the OP.
I'm still not sold on CP3 being this infinitely better talent than Rondo. Argue all day on how much better CP3 is. CP3 is absolutely not $5m/season better.
Beyond that, I don't particularly like CP3. There is just something about his personality and demeanor that irritates me. I'm sure I'd learn to like him if was in green, and would definitely root for him.
Also, they're just tea leaves, but, it does seem as if CP3 has no desire to play in Boston. Rumor has it his "people" have made it known he would not sign an extension here.