Seeing as we're all hopeless Celtics homers, everyone is bashing Jackson for cancelling the work out, and rightfully so. He shouldn't have agreed to anything he wasn't willing to go through, and even if he changed his mind he should have at least honored his original commitment.
I don't really want to talk about the cancellation though. What a lot of fans don't really want to admit is that as good an organization as the Celtics are, there are a lot of reasons this isn't the best place for a young player to come to now.
First off, the Celtics already have Jaylen Brown, Jae Crowder, and are planning to go all out to sign Hayward. That's way too many SFs eating up minutes. This is a team that wants to at least half "go for it" right now and honestly, that means young players are not going to get as many minutes as they would on a typical lottery team. The less a player plays early on, the less experience and exposure they get.
With such a logjam at certain positions and a requirement to maximize their ability to win now, eventually some of the players will either be allowed to walk or be dealt for a superstar. It's unrealistic to expect the Celtics to keep all these young players because we won't be able to afford them. Eventually the team will need to decide which ones are best and deserving of a big contract. The ones that aren't will either be dealt, let go, or asked to sign less for a bench role. The most likely result is that they are traded.
Why would a young player want to go somewhere where there is that uncertainty? You are totally under the team's control and could be dealt anywhere. Why not go to a place where you will at least get playing time?
The Celtics are trying to have their cake and eat it too. They want to compete now but due to the unlikely situation where they have all these good first round picks from the Nets deal, they are trying to use the kids as assets while keeping them as bench players. What's going to happen next year when they potentially have two more lottery picks? Are they going to have a bench full of lottery picks? How happy are they going to be in such a situation?
We already are at risk of keeping Yabusele and Zizic abroad another year, delaying their rookie deal activating and limiting the amount of NBA money they can make overall in their careers. Do you think that is making their agents very happy? With so many forwards, what is Yabusele thinking? Is he ever going to get a chance here anyway?
Undoubtedly the Celtics are going to be making trades to help alleviate the roster jam, so they'll be fine eventually. The players? That is debatable. Yes, when it comes down to it every player in this league is an asset, because after all it's a business. But when you're 19 years old, it's still important for you to believe that the team that drafts you truly believes you will be with them for 10-12 years.