This may have more to do with it than you might expect. According to a veteran CRC agent with whom I just had an interesting conversation, many of the changes over the years that we view as cheapo cost-cutting measures have actually been driven in part by whiny, self-important FFers who have ruined it for everyone. Spoiled elites who got op-ups and didn't get their kosher meals sued for discrimination. People voluntarily separating from their luggage by SDCing, yet later demanding that luggage be delivered to their hotels/homes on Delta's dime (an expressly waived service when you SDC), led to the rule eliminating SDC/SDS for those with checked luggage.