At least in Warsaw, there are various kinds of developers. Some specialize in luxury housing, while others cater to the mass market, with tall building of small-ish flats, hundreds of units per flat, built on cheaper land further away from the city center. There were entire districts built by such developers in the past 20+ years. Perhaps the key to this is relatively low regulation in Poland, which sadly results in somewhat chaotic urbanism and a lot of missed opportunities for building a city that's nice to live in, but also allows for shit to get done.