While the Arlington County Board started hearing out hundreds of citizens at its Saturday meeting about its “Expanded Housing Option” proposal to liberalize zoning regulations and enable the construction of multiple-family residences in more of the county, I went on a bike ride that took me through several of those single-family-zoned neighborhoods on my way to the Donaldson Run trail.

Many of the front yards I passed featured a yellow “No Missing Middle” sign supporting the current regulations, which only permit by-right construction of single-family residences in the vast majority of Arlington.

It’s not that you can’t build a duplex, triplex, quadplex or a tiny apartment building there if you really want to–but you’d better clear your calendar and have money to pay for a real-estate lawyer to navigate your project through the county’s Site Plan Approval process and have it voted on by one or more county commissions and then the County Board.

That took six months for one recent proposal to build a duplex a 10-minute walk from the Ballston Metro; another, which only involved renovating a 1935-vintage duplex, has spent years grinding through this process but remains on hold.

(Disclosure: My wife works for Arlington County’s government but has no role in housing policy.)

So while Arlington has done fantastically well at nurturing dense, walkable and transit-oriented development along Metro and bus lines, outside those corridors the county remains mostly single-family homes. Which are both getting increasingly expensive and at increasing risk of being torn down and replaced by giant homes built to maximize a lot’s development potential (and a developer’s profit), and which are only affordable to the wealthiest buyers.

We could have intermediate types of development like duplexes and triplexes–what affordable housing advocates call “missing middle” housing–but county leaders, like many local governments across America, chose otherwise in a series of actions that often reeked of racial and economic exclusion. In 1938, Arlington banned row houses outright; in 1942, another zoning revision limited duplexes to a small fraction of the county; a 1950 revision further clamped down on duplexes.

So when an existing house goes up for sale here, only two things can happen to it when the default setting is single-family dwellings: Somebody buys the place to live in and hopefully fix up, or somebody buys it as a teardown and replaces it with yet another 5,000-square-foot mini-mansion. I think about this every time we get an unsolicited letter from a realtor saying they have a buyer interested in the lot occupied by our 1920 bungalow–which we could only afford because I had the good timing to buy a condo here in 2000 and have it double in value by 2004.

Lot-coverage rules can tamp down building sizes and encourage neighborhood-friendly touches like front porches, but we can’t prohibit homeowners from optimizing a sale for personal wealth. Some places can offer property-tax incentives for keeping older homes, but in Virginia we’d literally have to amend the state constitution to add a carve-out to its clause requiring uniformity in property taxation.

The people who put those “No Missing Middle” signs in front of their 1950s-vintage homes–not to mention the one I saw in January in front of a row house built just before the county’s 1938 ban–seem blissfully unaware of this dynamic. And yet nobody here seems happy with how expensive housing has become or how bungalows keep getting replaced with giant, boxy abodes that only a couple with dual six-figure incomes can consider buying.

Partially deregulating zoning to allow more but smaller homes on one property, subject to limits about factors like parking spaces and lot coverage–also known as “giving the free market a chance to work” and “not having the government pick winners and losers”–is a feasible route out of this dead end.

It’s also the right thing to do. We don’t need to be yet another privileged place sticking with a housing policy that amounts to “Screw you, I’ve got mine”; as a pro-missing-middle editorial in Saturday’s Washington Post concludes with an icepick of a sentence, “One San Francisco is enough.”