It's as simple as the Sixers have really good wing defenders.
Other than Kemba, all our offense is from the wing. Jaylen feasts on poor defense, but his creation isn't their yet to be a primary guy against top level defenders. Jayson has been bad on offense all year, if his jumpers not falling he's basically a net zero on offense. The sixers don't allow the easy looks behind the arc and their good at defending the drive while closing out on jump shots. They basically stole our defensive formula from last year and turned on us.