said by xenophon 
:I see your point. It depends on how limited the device is but is not an inherent limitation of WiMAX itself.
It took a while for multiband cellphones to appear. No different with WiMAX devices.
It is an inherent limitation of WiMAX. The standard doesn't define any frequencies unlike GSM/LTE in which all bands that can be used are defined by a central body. Also each WiMAX provider decides to recycle some different band, its not that there are 2 competing WiMAX providers in the same band like with 800 mhz cellular and PCS and its just a software switch for which adjacent channel to log into.
