I wish that were true because it'd give me hope for getting some on-demand content in the future as well - but the cable boxes themselves use cable cards, per FCC requirements, so if it were a limitation of the card they would be affected too.
"Interactive features such as Video on Demand rely on the CableCARD Host device being an OpenCable Host Device and have nothing to do with the physical card. This makes the common use of the phrase "CableCARD 2.0" as a requirement for video on demand misleading, since two way services have been provided with the actual cards from the very beginning."
I believe our HDHomerunPrimes are considered to be "UDCPs" (Unidirectional Digital Cable Product), meaning the box itself only supports one way.
I think the problem is the on demand content uses lots of proprietary coding from the provider included only in their box's operating system itself, so retail two way cablecard devices are not available.
Not the best source, but the part I'm referring to is cited with a CableLabs paper. Bottom two paragraphs of the Physical CableCards section.