I think it's clear that the potential of the Sixers is through the roof with Embiid, Simmons, Saric, and Okafor. It's a fair point though that as a team, there are many reasons why they may not meet that potential. #1 has already been discussed at length , too many big men who need playing time and money. There is also chemistry and commitment to teamwork vs individual success regardless of player positions , which is difficult to get from young guys looking to get stats so they get paid. Then there are injuries , which do happen , and finally some players individually don't meet their own potential.
Just look at the Pacers when they had Artest , Jermaine Oneal, and Jonathan Bender. That team at that time was widely considered to have a ton of potential.
Also the Bulls with Rose's MVP season and Noah , Deng, Mirotic on the way etc. that some said would win 5-6 titles.