When will Metro-North get with the times?

My Hudson Raillink bus was almost late to the station this morning.  Tons of construction work going on in Riverdale thanks to all of the co-ops and condos in some areas...  Anywho, there I was cranky that I was going to miss my peak rush hour train to the city.  Ran to the ticket machine, used my credit card and violà, I had my ticket and my train was a bit late so no worries there, but an idea crossed my mind... Why can't you just use your Metrocard to buy Metro-North tickets?  I've had money value on a Metrocard for so long that I didn't realize I had anything on it until I checked this morning.  I need to buy unlimited Express Bus Plus cards due to my crazy schedule and tutoring, but in the meantime, it would be great if say you had money on a Metrocard and could use that to buy Metro-North tickets.