There are higher end USB 3.0 SDR's that can do wide bandwidth.
Perhaps. But not in the sub-$500 range and not without significant pre-processing in the receiver and TX chain outside of PC. The DVB waveform has many, many ready-made mixed signal/DSP ASICs "off the self" for embedment into OEM products. So I'm not sure what the point is.
And in that sense, it's just another version of the Flex-6600, IC-7300, IC-9700, etc., except thay are not DVB chipset based and are optimized for HF/VHF, etc. But they are "SDRs" as well, with USB ports. And go for quite a bit more than $500, too.
With the right FPGAs/ASICs/ADCs/DACs, GHz of bandwidth are not only possible, but commonplace.
Brian - K6BRN