This coincides with treating housing as an investment. Older generations (even Gen X) will flaunt how great it is that their house went up by X% in the last 5 years. It completely ignores that housing is meant to keep a roof over your head and not be treated as a spreadsheet line item in your portfolio.
We really don't though. If we sell our house, we have to buy another, and they have risen in price also. Basically, buying into the home market allows you to just keep your head above water, you can't actually get rich unless you sell your house and move to a cheaper real estate market, or you decide to speculate in property outside of your primary residence.
It's totally possible to have housing be "affordable" (i.e., condos, apartments in multi-unit complexes) and "a good investment" -- buildable land close to amenities/jobs/etc. rises in value, and so selling to a developer who will add more units on that land can net the owner a solid profit.
The contradiction appears when you want the same units (i.e., SFHs in perpetuity) to be both affordable and appreciate in value.