I'm not here to be a THT defender, but I also don't think we should be so revisionist about THT's time with the Jazz last year:
THT got the start at the beginning of last season and he didn't play too well, but the whole team was playing poorly. Was he a part of the Jazz playing poorly? Yes. Was him starting the reason why the Jazz were so poor? No.
After he was initially benched, he was still in the rotation and playing decent. The team was still struggling, but I would say it was similar to when he was starting. He wasn't amazing, but hard to put the struggles on him.
Things started to pick up for the Jazz once Kris Dunn got into the rotation regularly. He did not get into the rotation because they bench THT, but because Keyonte got injured (who had played horribly as the starter).
This is exactly when Sexton was put into the starting lineup and started heating up. The combination of Kris Dunn being in the rotation and Sexton playing is what sparked a huge improvement for the team as a whole. Keep in mind, this is also around the time Hardy had given up on Collins as a PF last season, so that mattered as well. This is when everyone started playing well, including THT. THT had started playing the best basketball of the season and this even included some starts. So what happened to THT?
THT got injured and then Keyonte came back from injury. THT was now out of the rotation almost entirely for two months and only played in spurts due to injury the rest of the season.
So what does this all mean? I think THT kind of got the short end of the stick last year. There wasn't a true log jam, but Dunn+Sexton played great while Key+Clarkson had priviledge. The former pair were certainly better and deserving of more minutes, the latter two were significantly worse than THT and arguably two of the worst players in the league last year. I don't really blame Hardy too much for any of this, it just happened to be the case that it was a bad situation for THT. I think THT's poor attitude didn't help the situation and that's also probably why he struggled to find a team this summer. I wouldn't say it was a huge mistake or maybe even a mistake at all for the Jazz, but it was good flyer by CHI.