Collins hasn't done a good job this year.
I think it's unfair to say he hasn't done a good job. He hasn't been playing with a full hand this whole season. And the expectations were thru the roof after being so close to the ECF last year. They let Brand, Lou Williams, and most importantly Iggy go. Holiday has stepped up this year, but any team would be hard pressed for wins if they lost 3 of there top 6 players without adequate replacements.
If they were playing this poorly with Bynum in the lineup then it would be fair to say Doug Collins is not doing a good job. But without Bynum in the lineup, Doug Collins is one of the hardest pressed coaches in the NBA.