A few thoughts here.
Most star players don't win anything until they reach their primes. Notable exceptions from the last 30 years are Kobe (won at 21 iirc playing next to Shaq), Wade (again, with Shaq), and Duncan (with the Admiral). Most take much longer. Giannis won in his eighth year at age 26. Lebron got his first in year nine after teaming up with Wade and Bosh. Curry got his first in year six after three years in college. Durant, year ten. Garnett, year thirteen. So struggling to get over the hump at this age is normal, even for players who - let's be honest - are a class above Tatum and Brown as players.
That said, it's absolutely fair to be frustrated at this. I know I am, to the point where I don't even enjoy watching this team most nights. There's no guarantee we ever cash in. I listed several guys who won later than one might "expect"; there's a much longer list of guys who "should have won" and never did. And none of us want our guys to end up on that list. Key guys could leave, get hurt, regress, retire, or anything else, and suddenly that window closes. We have a golden opportunity to win this year in a league with no current juggernaut, and we're on the brink of squandering it.
I don't think Joe is the biggest problem. He sure as hell isn't part of the solution, and I would have greatly preferred a coach with more experience to lead this group. But we're falling victim to the same s*** that has plagued us for the last three seasons, under three coaches. At some point it's less about the guy on the sideline holding a clipboard and more about what the guys on the court can do to be better than they currently are.
