1) Quick Service usually does not have a "Salad Bar".
. . . some have a salad option where they let you select toppings that the CM will add
2) That would make it an All You Can Eat. *
3) Disney does not like eateries where they cannot control the price and output.
4) I could see people just pigging-out on the salad bar and even taking some away food with them. *
. . . this is why the "Toppings Bar" at Cosmic Ray's was cut back
. . . people would use the fixin's to actually make a salad
. . . plus, they would take items away from the eatery for later *
* Alas, greed takes over and some try to get more than they deserve.