Can someone explain the economics of this? Presumably the landlords in the working class neighbourhood are already charging as much rent as the market will bare

Can someone explain the economics of this? Presumably the landlords in the working class neighbourhood are already charging as much rent as the market will bare. When richer people moving in, are they outbidding locals? Are the landlords looking at the new tenants and noticing they can charge more? Why is the rich person willing to pay more if, presumably, the apartments/houses in this neighbourhood aren't as nice as ones in other areas? Is it a slower, more secondary effect where over a period of time more rich people move in and somehow raise demand which leads to overbidding by a second wave of newcomers? Maybe I'm presuming too much, but I don't understand why rich people would be willing to overpay for "low quality" housing in the working class area? Are they actually paying market rent, but what's happened is that all of the current residents are somehow paying below-market rent?