In New York City, proximity to the subway is a decisive factor in real estate values. Lately, some urban reformers and liberal politicians have advocated taking some of that value back to fund the imperiled subway system itself, in the form of special taxes calculated specifically with this relationship in mind.

Value capture, as the policy idea is called, is “the solution of the moment” according to one business community leader quoted in the New York Times, and an “innovative financing mechanism” according to the president of an urban policy advocate group. Now, Governor Andrew Cuomo has gotten on board, making value capture a centerpiece of his subway system rescue plan.

It makes sense. Some private property owners benefit enormously from a publicly funded system, and it’s logical that they should pay a share of that additional, unearned revenue back into the system itself — especially because that system is in crisis. But value capture is also a complicated technocratic intervention, one that would require the creation of a new bureaucracy to evaluate the specific impact of transit lines on real estate prices over time, and entail a controversial and likely difficult effort to mediate between the transit authority and the city.

That doesn’t mean it shouldn’t happen, but it begs the question: in a city where billionaires pay one one-hundredth the national average in property taxes, why not just start by taxing the rich appropriately under the current system?

The formula that New York City uses to assess real estate values and property taxes is absurdly complex — and as Wall Street has taught us, complexity in finance tends to favor the rich. Current property tax law was put in place in 1981, in an era when homeowners were fleeing the city and taking tax revenue with them. The resulting policy featured some very unusual details. For example, to assess market value for residential real estate, the city began estimating rental income for properties that don’t generate rental income, like condos. (Supposedly that made more sense when the property values of condos and rental properties were kind of similar — before the massive boom in luxury condo development in the city — though some elements of the tax policy were inscrutable even in historical context.)

Since the outdated law benefits the city’s most affluent and politically influential residents, they’re not exactly agitating to change it. “New York City has since rebounded, of course,” writes Kriston Capps at CityLab. “And as a result, the property-tax burden has shifted from owners to renters, and from the wealthier to the poorer.”

The failure to readjust property tax law to meet current conditions has produced a situation in which expensive properties are dramatically undervalued for tax purposes. Today, a condo can sell for nine figures, but is taxed like a property that sells for seven figures. The owner of a $100 million penthouse in the gleaming One57, a skyscraper in Midtown known as “The Billionaire Building,” recently paid $17,000 in taxes. That’s a 0.017% tax rate.

Through this labyrinthine classification system that undervalues the homes — and the vacant pied-à-terres — of the rich, “The city is leaving money behind by failing to tax the most valuable homes at a rate closer to their market value,” writes Capps. “As it stands, the smallest sliver of New York’s wealthiest homeowners pays the tiniest fraction of New York’s property taxes.”

Unfortunately, establishment Democrats are inclined to miss the forest for the trees. Instead of straightforwardly addressing the glaring oversights and inequalities in the extant system, they habitually devote their efforts to developing Rube Goldberg-style policies that they promise will better balance the forces of power, in five years or fifteen, pending reelection. Democrats are particularly loath to make enemies of their liberal elite donor base, especially in major coastal cities where that base is entrenched in the political machinery. They thus tend to favor elaborate technocratic schemes that buy them time and make them appear hard at work for the majority of their constituency, but rarely deliver on their promises of social change — and therefore rarely bite the hand that feeds them.

This value capture idea is hardly any different. It is not a harmful idea: it rightly identifies the relationship between public infrastructure and private property values, and demands a proportional return on public investment. But it still mostly tinkers at the edges of a dysfunctional and blatantly unfair tax system that’s rotten at the core. A policy crafted in a genuine spirit of large-scale redistribution wouldn’t be so complicated — no differential assessments of transit line impacts on market values, no cross-departmental redistricting blueprints, no “innovative financing mechanisms.” It would start by simply closing the loophole that has billionaire property owners laughing all the way to the bank.