As someone who knows very little about WiFi, I always thought it sucked that if you wanted to go from 802.11this to 802.11that, it always requires brand new hardware with a different WiFi chip that implemented the new standard. Is there a good reason that software-defined 802.11 doesn't exist and that every new standard requires a different radio+SoC?
One example is the introduction of MIMO, a technique to send multiple data streams in the same frequency band in parallel. This requires multiple antennas, i.e. hardware which wasn't there in the previous wifi version. Note this was 2009.
