Yes, some mechanism for upgrading resale points to "blue card" status would be an easy cash grab for
DVC. However it stands to hurt direct sales and also makes more people eligible for the direct perks. If we take a high-demand event like Moonlight Magic, the fewer people who can book, the better the result for those who qualify. If DVC continues to sell new points AND provides a means for upgrading resale to qualified points, MM and similar events just get harder and harder to book.
Not saying they won't offer such an upgrade path. But there's an obvious downside for those who are paying full-freight for those benefits.