Housing data and consultancy firm Zonda tracks the entire building life cycle, beginning with what’s happening with raw land, into how that land is developed, and then what the homes sell for. This includes new home projects across the country and the percentage of those projects under $300,000. In comparing data from February 2019 and Feburary 2023, Zonda found the share of projects under $300,000 declining all across the country. 

From Texas to California to Colorado to Ohio, they are vanishing everywhere. San Antonio, for instance, experienced a 12% decline in the share of projects under $300,000 from February 2019 to the same month this year, while Houston experienced a 16% decline and Cincinnati experienced a 29% decline. Still, all three markets were on the higher end, with current shares of homes under $300,000 at 34%, 28%, and  22%, respectively. The share of projects under $300,000 i nonexistent, coming in at 0% for the markets of Riverside and San Bernardino (grouped together as one), Denver, and Sacramento, down from 3%, 4%, and 2%, respectively in 2019. 

As of 2021, the real median household income in the U.S. was $70,784, according to the Census Bureau, while the average home value in the U.S. was $297,030 by the end of 2021, according to Zillow—that’s more than four times the average household income. With the share of projects under $300,000 declining, so is affordability, simply put. Ali Wolf, Zonda’s chief economist, is alarmed at what this means. “We’re creating, inadvertently, a renter society not because of choice but because of force,” Wolf told Fortune. 

Wolf, who shot to stardom during the Pandemic Housing Boom as a go-to expert on the exploding market, appearing several times on Bloomberg’s Odd Lots podcast, as well as PBS NewsHour, among many others, said that homes costing under $300,000 are essentially “attainable housing,” and almost everyone “should be able to afford a home under $300,000, that is within the realm of what’s reasonable.” Wolf said the question of why they’re disappearing has a “complicated answer,” related to factors including the cost of building materials, land availability, the cost of labor, the lack of housing supply, regulation, and zoning. 

“To get a lower-priced home built under $300,000, you’ll either have to build a smaller home or homes in a higher-density setting,” Wolf said. “And oftentimes there’s resistance to that kind of change, either from city officials or from the NIMBY-ism movement”—every market’s not-in-my-backyard contingent that typically opposes new development in their neighborhood because, they say, it will either bring property valuations down or affect their quality of life, or both. 

But that’s not all: “A lot of it comes down to the Pandemic Housing Boom,” Wolf told Fortune, as builders are trying to build homes quickly to meet demand, and that sends prices up. With mortgage rates at historic lows, the demand pool increased as more people were able to buy homes, pushing costs and overall home prices up.   

“So it was really kind of this cascading effect that started with affordability,” Wolf said—because that increased the buyer pool, increased the need for building, and increased the cost of what goes into building, ultimately pushing home prices up. 

At this point, the data is telling us that “we need to get serious about changing how homes are built,” Wolf said, which could mean increased density and smaller homes. That being said, because of the surge in demand, Wolf said, we’ve almost lost sight of how many people are not going to become homeowners because of how high home prices have gotten. That’ll create a “larger imbalance between the haves and have-nots in the economy.” Wolf said.

And it’s not going to get better anytime soon. In the next couple of years, Wolf said, she expects the share of attainably priced homes will continue to go down in most, if not all, markets across the country.

“It’s a wake-up call,” Wolf told Fortune. “It’s a wake-up call that we need to be doing something differently.”