New York’s housing market is already tight. The share of housing units available to low-income households fell 12.9 percent between 2006 and 2016, according to a 2017 report from NYU’s Furman Center. The city said in September that it has lost more than 400,000 affordable housing units since 2005. Meanwhile, the population of the DC metro area has increased seven percent since 2010, but the number of housing units has grown only three percent, according to the Urban Institute. There are signs that this is changing the dynamics of who lives in the region: the number of renters with incomes between $100,000 and $149,000 has grown 58 percent between 2000 and 2018, according to the study, far outpacing growth in renters with incomes of $50,000 to $74,999, which grew just eight percent.

Of course, there is no guarantee that the presence of new tech jobs in New York and Arlington will create the same problems that tech job growth created in Seattle and San Francisco. “Things like a major relocation or HQ expansion should be a very positive thing—but it takes a lot of intentionality to make sure that’s the case,” said John Lettieri, the president of the Economic Innovation Group, which researches what makes cities and regions successful.

Officials in New York and Arlington say that they have a plan for the influx of new residents. When New York mayor Bill De Blasio was asked by reporters at a press conference how he was going to make sure that New York didn’t follow other cities’ paths to unaffordability, he dismissed the question. Seattle and San Francisco “are totally different places than this,” he said. New York is planning to add hundreds of thousands of housing units over the next few decades, and the growing tax base from Amazon will afford it more money to invest in housing and transit, he said. Arlington County and the city of Alexandria promised an investment of $570 million in transportation projects to help accommodate the growth that Amazon would bring. The state of Virginia also said it would invest $195 million in infrastructure for the neighborhood. Arlington projected that around 2,000 affordable housing units would be created in the area in the next decade.

But even if Arlington and New York are able to create some affordable housing, it takes years to build new housing units, and it’s unlikely that the cities will be able to create enough units for next year, when Amazon says it will begin hiring. It takes longer to get approval to build new housing units in cities like Washington and New York, and no part of the Amazon plans mention how the cities plan to speed up this process.

There are, of course, other problems with Amazon’s HQ2 bid. There’s the time wasted by cities and state legislatures preparing extremely detailed pitches at Amazon’s request—which took more time than most economic development proposals, Sam Bailey, the vice president of economic development at the Metro Denver Economic Development Corporation, told me last week. There’s the unprecedented cache of confidential information cities gave to Amazon about development and infrastructure plans that it hasn’t given to anyone else, even the public. There’s the fact that Amazon may have known from the start that it would have to place its new offices in superstar cities like New York and Washington DC where highly educated people live.

But the most striking thing to remember is that Amazon is big enough to change the fabric of the regions where it locates. And as it has in other places, it may make big winners out of some people, while making life more challenging for everyone else.

We want to hear what you think about this article. Submit a letter to the editor or write to letters@theatlantic.com.