Would a top chef really be content making sandwiches?

I think he was content more because it was his decision to make those sandwiches as opposed to someone else deciding it for him.

i agree , fter the 3rd stop-to-sell in the film i was thinking: that just looks like hard work and little fun

Wolfgang Puck makes pizzas.

He wasn't. He opened the restaurant at the end to get back into food-as-art craftsmanship. But the food truck served to help him rediscover what he loved about cooking in the first place. It stripped away the artificial layers of BS that come with trying to cater (pun intended) to regular customers, deliver for food critics, and where you're worried as much about ambience as the dish itself. It helped him just focus solely on making good, basic food that people love, and that re-focusing kindled the dying embers of the artist within him.