I believe that limited reservation availability was explicitly listed in the terms of these specially-priced ticket deals. I think it is reasonable for Disney to make more reservations available to those who paid more for their tickets, as that is the type of purchasing behavior (buying full-priced tickets) that Disney wants from its guests.
Here is the detail from the So Cal ticket offer page (bolding is mine):
To enter a park, both a
theme park reservation and a valid ticket for the same park on the same date are required.
Theme park reservations for Southern California Resident Ticket holders are limited in number and subject to the availability of park reservations allocated to the Southern California Resident Tickets as determined by Disney, applicable blockout dates and theme park capacity. Reservation availability for Southern California Resident Ticket holders is not guaranteed for any date and reservations may be difficult to get for any particular date, especially as the ticket expiration date approaches. To ensure best availability, make reservations early. On any given date, park reservations may be available for general theme park tickets even though park reservations allocated to the Southern California Resident Tickets are fully reserved.
Southern California Resident Ticket holders are not entitled to any reservations Disney makes available to others. Parks, attractions, entertainment, experiences, services and offerings may be modified, limited in availability or unavailable, and are subject to restrictions, change or cancellation without notice. Park admission and offerings are not guaranteed.
View important information about what you need to know before visiting the
Disneyland Resort.
To purchase by phone, call (800) 859-8269 to speak with a vacation-planning expert. Guests younger than 18 years of age must have parent or guardian permission to call.