No one can do it alone. But Jeff couldn't do it with an all-NBA roster, either so..
When did Jeff have an All-NBA roster?
Last year he was playing behind Pierce and KG, both of whom were a shadow of their former selves come playoff time last season. It's also worth mentioning that Jeff Green was an absolute BEAST in that playoff run. He averaged 20 PPG and was arguably the Celtics best offensive player.
The season before that he missed due to heart surgery.
The season before that he was traded half way through the season and had a inconsistent role with inconsistent minutes.
Jeff Green is not an Alpha-Dog type of player. He's not a guy who's going to give you 20-25 PPG and be your go-to guy on a good playoff team every night. If he was that type of guy he'd be getting paid closer to a max contract (around the $13M-$15M / year range). He's more like an Andre Iguodala type player - a guy who gives you some good defense, while also being a nice #2 or #3 option on offense. He'll put up 20 points every 2nd or 3rd game, and every now and then he'll explode for 30.
I think he's played that role very well this season.
Jeff has scored:
* < 10 points 14 times (17%)
* 10 - 14 points 17 times (21%)
* 15 - 19 points 29 times (35%)
* 20 - 29 points 18 times (22%)
* 30+ points 4 times (5%)
So for those who constantly complain about Jeff's inconsistency, the above stats show that he has scored between 10 - 29 points in 64/82 (78%) games this season.
Based on the amount of money Green is being paid ($9M / year) and the type of role he is expected to play (#2 - #3 scoring option) I don't see how you could consider those numbers below par. Especially when you factor in the consistently excellent defense he has played over the course of the season.
People keep looking at Green the wrong way. Keep saying his production hasn't changed when he's had more talent around him. That's correct, and it won't change. I don't think anybody is saying that Jeff Green would be a 20 PPG scorer if he had a go-to guy on the team. He'd still probably score 16-18 PPG. The difference is that his efficiency (from three and from the field) would likely improve significantly. So suddenly people would start judging him based on what he is (a #2 option) rather than the current scenario, where people are judging him based on the role he has been forced in to (rather than the role he is realistically suited to).
You can't blame Jeff Green because you have set your expectations too high, and he didn't meet them. If you expect more from him than he can give (and is being paid to give), then that is your own mistake. That's no fault of his.