The depth on this team is overstated in terms of talent gap between players. No doubt the Celtics have 11 NBA caliber players, but IT, AB, Sully, Smart, and Crowder are far and away our best players. Too often, people only focus on offensive talent. Of the five players I listed, three of them have an argument to make the all defensive team. There is a huge drop off in defensive talent after those three. They hold this team's defensive identity together. Finding a defensive trio as talented as the three we have is no easy feat. There is a whole other side of the floor, and our whole perimeter except IT plays it better than any other perimeter in be league. In a league that is shifting towards small ball, it cannot be understated how valuable that is to have. A 6 for 1 trade would destroy this team, at least in the short term.
No other player on this team can average 20 PPG like IT. No other player on this team shoots as well as AB. No other players on this team can defend like Smart, Bradley, and Crowder. They are currently the soul of a top 3 or 5 defense. The talent on this team has been underrated for quite some time now. We have one all star level talent and three all defensive level talents. That's 4 high impact players. Without them, this team circles the drain. No superstar, but this team definitely has talent that has separated itself from the pack.
So yeah, trading Smart, Thomas, Bradley, Sullinger, Amir, and Crowder for one guy who has never won more than 30 games would significantly hurt this team. You would be banking on Rozier and Hunter to develop and replace Thomas, Smart, and Bradley which may never happen. No proper replacement for Crowder either in that trade. Cousins isn't good enough to make up for the lost impact of those 6 guys.
The Celtics would go from having one of the better overall perimeters in the league with a capable front court and a team deeply entrenched in its defensive indentity to a team with a junk perimeter and the best center in the league who has questionable defensive motivation.. Doesn't sound great to me.
The Harden example is even worse to me because we are literally taking away every good defensive player from this team and replacing them with a guy who literally plays no defense and completely dominates the ball. If you want success with Harden, you need to surround him with 3 and D players and have the best offense in the league to make up for his terrible defense. That isn't happening with that hypothetical line up. You are basically taking every impact player off this team and replacing them with only one guy who is pretty much IT x 1.5. Probably looking at 30 wins with that team.
Look we need a superstar to compete for a title, but I'm starting to think people are overrating a superstar's impact while underrating what a collection of above average starters with one low tier all star can achieve. No superstar can make for that much of a talent loss except maybe Lebron. Most of these 'true' stars have significant flaws themselves, and they are not a heal all elixir capable of replacing the impact of those 6. We don't want to make the same mistake NY made when trading for Melo.
There simply isn't as much parity on this roster as you think there is. IT and AB are far and away our best offensive players. No other player on this team touches them there. After that there is some offensive parity; however, the difference in defensive quality is vast. This team isn't a top 3 defense if you are running JJ, Lee, Turner, and Zeller out there in replacement of Smart, AB, Sully, and Crowder. Offensive parity sure. Overall parity? Absolutely not.