It's a good point: someone who either won't fix the rack to the ground or won't opt for attached plate storage would face some serious stability issues with a light 2x2 rack. Are there cases where commercial pin and pipe safeties fail in good repair though? I won't completely dismiss the second part of your remark but it seems a little silly to me.
Rogue sells one I expect it's not compatible without other brands--actually that might violate some anti trust laws.
EDIT: Callador, the one Rogue sells isn't adjustable in the direction of the bar like a regular monolift. It may not actually give you much extra hand space. Although I'm looking at it and I don't know why it wouldn't fit any other rack with the same tubing. Says it's only compatible with Rogue racks on the website though.