Pre-prepped doesn't necessarily mean poor quality. In the UK, a very very small percentage of restaurants serving a 'full English breakfast' will make their own sausages, or their own baked beans for example. You can purchase excellent pork and leek sausages from mass catering companies, that have won blind taste tests.

The soups we used to buy in at one place where I worked were fresh, never frozen, but vacuum sealed so could be kept in the fridge on hand - they were made at a small farm shop, from organic vegetables, no artificial ingredients, and tasted pretty good. Were they as good as if we had made them fresh on site that morning, probably not, but they were pretty decent.

You'd also be very surprised, I would wager, by some of the 'higher' end restaurants, what they actually buy in pre-prepped, simply to save on staff labor costs. One of the largest catering suppliers does what I would lovingly call 'boil in the bag' but what chefs prefer to call 'sous vide' dishes that you literally shove in hot water, then snip the corner off. Lamb confit, a venison and red wine stew, chicken chausseur, all aimed at higher tier restaurants (just take a look at the truck name that delivers their food, and then look at what that company offers in terms of pre-prepped food, it is enlightening!)