Sway caused accident on I-75

At the risk of offending some, I have always wondered why some folks will declare with great pride that they've towed an X' trailer a zillion miles through all sorts of weather and never had a problem and they've never had sway on their rig. It just seems like extra protection - not only for those in that rig, but the ones traveling the same road - and is relatively inexpensive. If you're going to spend a bunch of $$$$$ buying a great camper, spend more $$$$$ to have an adequate TV, invest in a hitch to handle the thing, why not have sway?? Not a criticism, but something I've never understood. Why NOT??