J.K.
Why worry?
Do you have nutritional concerns?
Is it the cost of jarred food?
For nutrition, a good range of jarred food should be fine. (I'd use organics, myself.) You could add fiber with snack-y fiber treats for kids and a toddler vitamin.
The cost, I can sympathize with. Maybe a Costco run to last him through this stage?
I would not deprive him of jarred food in an attempt to get him to eat potatoes or spaghetti. In this crucial time in his brain development, your son needs enough protein, fat and calories to fuel all taht growth and development.
I'd keep offering other foods, along with his jarred food, and my guess is that within a couple of months, he'll be eating a greater variety. In particular, a 2 year old is likely to rebel against something you try to enforce arbitrarily.