Who has the better future Sixers or Celtics?

This series of the future of the NBA has been very interesting to watch. Both the Sixers and the Celtics are pegged to have incredible futures and dominate the NBA for years to come. This series has been incredibly interesting to watch as, the Celtics without, arguably, their two best players went up 3-0 against the Sixers who were coming into this series looking invincible. The Celtics have a chance to close out the series in 5 at the TD Garden Wednesday night. The Celtics have a mastermind as a head coach in Brad Stevens and a system. System's work in the playoffs. The system is not off one player but a team and Brad Stevens is just a wizard, adapting to the strengths of players he has in front of him. Without Hayward and Irving the Celtics still look ECF bound and that is absolutely crazy. Yes, this series is probably over, as no team in NBA history has come back 3-0, but who will win the next 5, 10, 15 years? Here's my take. 
The Sixers and Celtics are both extremely talented young teams. The two best young teams in the NBA. Who is the best young team? Both teams, have different things going for them.

The Celtics:

Boston has a great mix of youth and vets. Their young guns like Tatum, Brown, Rozier are blossoming into potential stars. They still have solid vets in Kyrie, Hayward, Horford, Morris. On top of all this, they still have Brooklyn picks at their disposal and can clear space for a max-level contract. With Kyrie and Hayward in their prime, this team will be in title contention as soon as next year. The NBA should very scared of this team. On top of this mixture of players, a mastermind as their head coach in Brad Stevens. Brad just makes players better, hiding their weaknesses and focusing a system around everybody strengths. A magician drawing up plays and getting his team to execute.  

The Sixers:

The Sixers have the star power. Two players that look like once in a generation type players. Embiid and Simmons drawing comparisons to Kareem and Magic, that is high praise but they're really good. Two players that could be future MVPs and All-NBA talents in this league. The Sixers are very lucky two have these two at the helm, as their future looks very bright. On top of that, Saric, and Covington add more young pieces that can help. They also have an open max-slot for a potential blockbuster free-agent. This team is very talented and no doubt will be a force to wrecking with for years to come. Also having Markelle Fultz can not hurt as he was the number 1 pick in a very talented draft. He should recover from his injury and be back on track next year. This gives the Sixers even better chances to succeed as Simmons will have another ball handler to rely on.

Yes, both teams have bright futures but who will be better? As it stands right now I would have to say that the Celtics are poised for more success for the next 5 years. What they have been able to do this postseason without Kyrie or Hayward is just absolutely ridiculous. They also have the organizational stability as their GM/ President of basketball ops is as secure as he can be and they have their coach for the future. A big part of their future success will be because of their mastermind, genius of a coach in Brad Stevens. He is just a very elite coach and having him for the future will only help. Brown, Tatum, and Rozier are getting better every day and expanding their games. As soon as Kyrie, Hayward and Horford sort of fall of this elite level, their young bucks will be able to take over and lead the team. On top of all this, they have plenty of assets which they can trade for a superstar like Anthony Dvais or Kawhi Leonard if they become available. This team has superstars ready to lead as soon as next season and players who will be ready to take the lead when the current fade out. The Celtics are the better team for the future 5 years at least.

Now predicting a team for the next 10 years is literally impossible. Imagine saying in 2008 that the Cavs would have Derrick Rose, LeBron James, Dwyane Wade, Kevin Love and Jeff Green. No one would have believed them, and no one would have thought they traded half the team for role players. So it's hard to predict to say the least. However, I'll take the Sixers just based on their young star power. In 10 years, Kyrie Hayward and Horford would be well past their primes. When looking at both young core I would much rather have Simmons, Embiid and Fultz compared to the Celtics Rozier, Tatum, Brown. The Celtics young guns are good but the Sixers have two future MVPs and star power can drive a team. They would also be my pick for the best team in 15 years. Their star power is too good if they are able to stay healthy and together, the Sixers will be better in the long run than the Celtics because they have the better young guys.