I have just now tried to use the newer online Disney reservations and I have noticed that everytime I check, the Magic Kingdom view options do not show up. Have they stopped booking them that way or are they just all filled?
Maybe it's your dates are sold out because I was checking the Poly and GF for 5/20 -5/23 earlier this evening and they both had the category "Theme Park View" (MK view) for my dates.
For my dates at the Poly, the Garden view was least expensive, then Lagoon view, then Theme Park view, and Lagoon view concierge was highest offered for those dates.
The GF had Lagoon view, then Lodge Tower, then Theme Park view, Standard room club level, ending with Deluxe room king club level as most expensive.