A major thing Jobs learned in between his tenures at Apple is that it's not enough to design great products, you also have to design a great business model that can deliver them to market. Business model design is just as difficult IMO. (He learned this at Pixar positively, and at NeXT negatively. Pixar's campus is a great example of business design, along with their deal with Disney. This skill also sheds light on why he hired Tim Cook so early after his return to Apple.)

Whether Jobs would have learned the same without NeXT/Pixar is anyone's guess. I suspect he would have.