Meh. Remember all the people back in 2002 who swore they would not fly until TSA was abolished and that they would drive long distances instead? I am certain that there are still a few of them. But, not many. Same here. If DHS orders this and it is challenged and not halted immediately, the litigation could take years and that means back to driving.
No idea what TSA is proposing to use here for technology, but most airports which do this in such a way that there is close to no delay, e.g. people walk at a normal or close to normal pace.