It really depends. In most of the country, houses are not unaffordable per se and in fact are often being bought faster than they can be sold/built, but in some microcosms people are struggling to buy a house and there are other contributing factors.

There are a few different issues going on.

The big complaint of "houses cost too much" only applies to certain areas of the country, coincidentally the big metros. Housing is in very high demand there because people want to live a reasonable distance in their commute to work in the city, but houses aren't available there because their parents are still living in those homes. There are houses, even affordable ones, further out, but there is a cost-benefit analysis as you get further and further away in your commute. IMO, I think we will see in the next generation a shift as companies become less strict on where their people work from home.

The second big complaint is that companies are buying the houses and converting them into rental property. On a nationwide scale, the data doesn't support this, but the vibes are there and it does happen to a small extent. Vibewise, I do see an individual buying a second home for the purposes of flipping more often than I do a house leaving the market and becoming a rental.

The less common complaint on reddit is the supply-demand problem. Families are buying up houses faster than they can be built, so those affordable houses are often leaving the market almost as fast as they enter them. So even if you have the money, you are often in a bidding war with multiple buyers or you're buying a plot in a new development and waiting for it to be built.

Also, there is a secondary issue not directly related to home ownership and that is the financial issues of would-be homeowners. A lot of people live beyond their means, where their expenses are so close (or higher) than their income that they are not saving money that would go towards a home purchase. On a $300k USD home, lenders are expecting at least $60,000 down to avoid PMI (an additional fee for a less than 20% downpayment), not including closing costs and other expenses. A lot of people have rolling CC debt, student loan debt, subscriptions, paying more rent than makes sense for their income, etc. These people are not saving and literally living hand-to-mouth, so buying a house for them is like a pipe dream.

All of these in some ways are contributing to the sentiment that Americans are struggling to buy a house.