Apple didn't make PowerPC chips. That's a huge difference.
First, Apple wasn't a supplier. If Silicon takes off, they could become a supplier. Second, the reason they're switching to Silicon is the same reason they switched from IBM to Intel - the chip suppliers didn't react to the changing consumer landscape.
By making consumer devices, Apple is much more in tune with that landscape than IBM/Intel is. They can adapt chips much better and won't be handcuffed by chip suppliers in the future.
First, Apple wasn't a supplier. If Silicon takes off, they could become a supplier. Second, the reason they're switching to Silicon is the same reason they switched from IBM to Intel - the chip suppliers didn't react to the changing consumer landscape.
By making consumer devices, Apple is much more in tune with that landscape than IBM/Intel is. They can adapt chips much better and won't be handcuffed by chip suppliers in the future.