Not sure if the really cutting grass could be a thing, but if it was I would not care if the mower was slower than walking then maybe when we could mod vehicles we could go all Tim the Toolman Taylor with it and ad a jet engine
any chance of a riding lawn mower? you know so we can knock back some of Grandpa's Moonshine and cruse around the apocalypse in true red neck style maybe even cut some grass along the way.