Just as an example, in addition to the prep time your pasta sauce adds one sautee pan, one chopping board, one chopping knife and one garlic press additional washing up (about double the washing up load). It also requires presence during an additional 10 minutes - although the pasta itself takes only 10 minutes to cook it does not require presence in the kitchen except to transfer boiling water from kettle to pot.
So in total we're looking at around double the trouble or more to prepare the meal with a home prepared pasta sauce as opposed to the pre-prepared one, not counting the additional shopping time and effort in selecting and buying the ingredients. I believe the stir in sauce to be more healty than not, and is passably tasty, so my home made sauce would have to be pretty damn delicious and be noticably better for me to be wothwhile. I just don't think it is.
It's another matter altogether if you enjoy cooking, and find preparing a pasta sauce a rewarding task to undertake, I suppose.