Plenty of homes in rural NE that (while not as small as this) are still well within the 60% mark for garage ratio. They tend to double as workshops or large enough space for farm vehicle maintenance.

Considering the amount of rural settlements and farmlands / ranches around the US, I’d say it’s not necessarily unreasonable. Can even find them in suburbia, albeit more rarely (have in-laws with the living space lofted over a full garage, which would put it at ~50% minimum before accounting for interior walls.)