Yeah but joking aside this is for the benefit of the guys only. If the doctrine changed and women no longer believed it was a “get to Heaven” issue and had a choice, how many would choose to share vs having their own home and their own man?
I expect quite a few would still choose a polygamous household, but the power dynamics would be VERY different, and I doubt most of these particular men would stick around for it. It's one thing to boss around 10 wives, and a very different thing to have 10 wives ganging up to boss YOU around. Absent the "be perfectly obedient to your husband or you won't get to Heaven" crap, the latter is likely how it would be.
I would guess “not many.” Sharing wouldn’t work for most, not even sure it works with polygamists.