In a way, they do. But, most discount perks, like Dining perks, are not solely under the control of DVC or Disney. Many are offered by privately held venues, like Ghiradelli, Raglan Rd, Landry's (Rainforest/T-Rex/Yak & Yeti), and so on. Many WDW restaurants are not Disney controlled, so those venues may offer those discounts differently.