Polygymists had to be able to financially support their wives, their different households and their children to each wife.
So it seems it is only for the wealthier men to pursue. Is this true?
Not so...
One of the stupidest stereo-types is a harem full of women lying around all day long with nothing to do.
Even the Bible says, "Let those who do not work, neither let them eat."
(2nd Thessalonians 3: 10)
This doesn't exempt that husband from dealing equally with all his wives with regards what he does allocate to them, and all have rights of inheritance including their children.
Statistically, the majority of polygynist households are in largely agricultural areas where everybody is working.