5 working women and one working guy get married. That is six incomes combined. If each woman had a child that is six incomes with 11 exemptions. Big gov stands to lose while the combined income of the family will afford it a good standard of living vs the tax rate of similar traditional couple with two kids. If each wife takes turn watching the kids (no daycare costs). There is lots of advantages to polygamy in terms of taxes and income. If sodomy (less acceptable and practiced in human history) is legal then the barriers to polygamy (more widely practiced by people in the past) should be lower.
Anyone forces someone to marry is abusive no matter if the marriage is traditional, gay or polygamy. If all the adults consent, the US gov and state gov has no grounds to make it illegal, especially after gay relations (two consenting adults) is made a human right. The state cannot assume polygamy arrangement is automatically abusive and continue to keep it illegal. It is like assuming all men have a penis and should be made illegal to prevent women being raped.
Abraham, King David, King Solomon, Simeon, Jacob, Esau, Gideon, Moses, etc., etc...
Polygamy assures a surplus of males who will never find a wife. Look up the “Lost Boys” issue caused by polygamy in Utah.
Moses had it right:
1. Man & woman contract a marriage for life - with G*d as a witness.
2. Divorce was available, under certain conditions, costly ones.
Joseph Smith was something of a satyr and abused his position to justify his sexual predations. America dealt with this once, and may again have to so do. Oddly enough, my Mormon friends are not eager to see polygamy resurfacing.
I don't think it would work out the way you are suggesting.
Six households with $30k each would probably pay NO taxes.
Each exemption reduces taxable income by $3.7k, I think.
One household earning $180k, even with 11 exemptions worth about $40k, would leave $140k in taxable income.
The progressive nature of our income tax would, I think, punish households with lots of wage earners.
If you don’t stick with THE definition, there is NO definition.
The left thinks they can let the snowball roll just “this far” down the hill.