Boost and Virgin Intro 4G Service Plans and Devices

Why dont they just release all or divide the rest of the Wi-max phones for boost / virgin mobile to use? Its not too may many of those phones and since they are pushing towards LTE and not making any more phones for Wi-max it would make sense unless they want to release them here & there to make more money down the line or they felt these 2 phones were the best option for either carrier and chose to leave it at that. Here are the list of the other Wi-max phones

HTC EVO 4G
HTC EVO Design 4G / Hero S (CDMA) - Boost
HTC EVO Shift 4G
HTC EVO V 4G / EVO 3D (CDMA) - Virgin
Motorola Photon 4G / Electrify
Samsung Conquer 4G
Samsung Epic 4G (Galaxy S)
Samsung Galaxy S II, Epic 4G Touch
Samsung Nexus S 4G