Let's be clear: the Porsche pick-up (as of now) is its own program where they try to pick up Diamonds on short connections first, then Diamonds going home/etc., then other HVC's on short connections, down the list, etc. Remember its not a guaranteed or published service (as of now).
DL may or may not have other programs for High Value Customers, but the Delta car and escort to plane services are not mutually exclusive as the WSJ article suggests they are for UA. @:-)
But I hear changes are a comin' as DL invests in new technology, programs and facilities in key cities to support say, maybe their top 1,672 customers. And because this is FlyerTalk I'd stress that would be top 1,672 spending customers, not folks on milage runs.