You could also blame air traffic who could have seen the gear was not down and instructed a go around , it used to be a check on mititary airfields that the tower did exactly that .
ATC are not responsible for checking whether the landing gear is down on final approach. Yes, it is perfectly possible for a controller to see whether the gear is down or not, but not always on a small aircraft like a Duchess, not always without binoculars, and not always if the controller is occupied with a number of other aircraft in or joining the circuit! Controllers often do spot things such as towbars attached to nosewheels, leaks from fuel tanks, taxying aircraft dragging tiedown weights behind them, and yes, forgotten landing gear - but these invariably result from a 'that doesn't look quite right' glance rather than a detailed inspection of every single aircraft through binoculars.
Given that there were three people in the aircraft who could have seen an incorrect gear indication, blaming ATC for not seeing the gear problem is a bit of a low blow. On military airfields, I believe that the visual check of landing aircraft was done from a dedicated 'caravan' positioned near to the runway threshold, not from the tower.