I said Timberwolves. They have two legit stars for future. 76ers are about there in terms of raw talent. Lakers and Celtics follow, and I think even Lakers are better suited for future in terms of talent than us - currently. This might change with trades, draft, and a huge Jaylen breakout.
But I believe having the correct coach is also very important. We probably have the best one, followed by Walton - I don't trust Thibodeau over the course of 5+ years. 76ers are the least lucky in that regard.
As an organization, Celtics and Lakers are the most "cool" with dealing with success and pressure. Wolves have never been there yet. 76ers have been gone so long, they might have a problem dealing with being called a contender - at least at the start.