Thank you for giving the History Central article. I see the data you used to make your conclusion.
I will show you what data I used. I present to you a US Department of the Treasury article (Figure 1):
https://home.treasury.gov/news/featured-stories/labor-unions-and-the-us-economy
And a US Congress Report (Figure 1):
https://www.congress.gov/crs-product/R47596#_Ref136534186
The data in the History Central article is represented in the graph and table in the US Treasury article and the US Congress Report. Where else would they get it?
For home ownership rates, that data can be found here:
US Department of Housing and Urban Development:
https://www.huduser.gov/portal/pdredge/pdr-edge-housingat250-article-071025.html
US Census:
The greatest increase in home ownership rates happened during the rise, at the peak, and just after peak union membership.
I am not defending the view that unions don't force unnecessary jobs, they do.
But the viewpoint that union power is unnecessary to a good life for a majority of people is factually incorrect.
Unions power did increase the power of workers and gave the generations that built that movement (the Greatest and Silent generations) and the subsequent generation (the Baby Boomer generations) benefits such as the modern welfare state and larger share of the income of productivity that bought homes and feuled consumerism.
Baby Boomers had a preceding generation that had 33% union membership rates and the 1% taking a smaller share of income (10%). Gen Z does not (currently unionization is at about 9%). History is important, history does not start anew when you are born so saying Baby Boomers had below 30% while ignoring the history just prior to it is not honest.
The question your asking is why is it that Gen Z/Mellenials don't have homes but boomers do? Which is good.
But, your other question should be why did a higher percentage of the Greatest and Silent generation have home ownership as opposed to the Missionary generation?
Homes were simpler to build back then, you could built it your self in the middle of nowhere.
I will change my view if you can show a situation where industrialization occurred but without increased unionization rates nor worker/consumer friendly government policy leading to higher home ownership rates. Any country would do.
If you can do that then you would have shown that neither union membership nor worker/consumer friendly government policy are necessary for large home ownership rates.
I have provided primary sources with long historical views. I hope you keep to that same standard as opposed to secondary sources with short historical views.