I'm one of those that would like to have a folding ROPS for my
BX2200. Since Kubota does not offer one, and I've checked some aftermarket ROPS builders and so far they don't offer them either, at some point I MIGHT mod mine to make it fold, buy a folding one that I can mod, or build my own. (I know, it is risky and we've discussed it ad naseum here.)
IF I do that, I plan buy a factory standard ROPS from Kubota and remount it to the 2200 at the point I ever sold the tractor. When it leaves my possession, it will be factory original.
Now I might sell the new owner a pile of iron that happens to look like a folding ROPS to fit the 2200, but the tractor I sell will leave my premises factory safe. What the new owner chooses to do is his decision then.
That's my plan anyway.
As far as Jeeps/dune buggies vs tractors, I think there has been more focus on making tractors safer than dune buggies. Not sure why, but manufacturers spend a lot of time/money designing and building ROPS and cabs that withstand roll overs, side impacts, front/back impacts, etc. Probably an OSHA standard they have to meet to have a certified ROPS/ cab.