Absolutely he should've and glad he did.
Horford took the team to the next level.
Not landing Durant doesn't negate the Horford signing in any way.
I also still don't understand why some think Horford is past his prime and playing in the twilight of his career.
Sure, he's not the same player now he was 5 years ago but he still gets the job done. The issue is, he's playing out of position which is why the Celts need a center to pair with Horford.
Not to mention, Horford comes off as a very classy guy who goes about his business very professionally. Similar to guys like Jim Thome, Mike Lowell and Ray Allen (minus Ray leaving Boston for Miami.)