Cutting through a lot of social commentary that is far more endemic than just around Hopkins or other large campuses. Very well deserved but a narrower focus is a better basis to start answering the question.

A lot of them have grown dramatically during official and non official redlining years. A lot have also grown dramatically over the last 70 years- more specifically the last 50. None more so than the Johns Hopkins system. All at the same time that Baltimore went through a dramatic decline in economics and property values.

It’s a combination of preferential treatment for a large and extremely influential organization, unabashed capitalization on low prices and “cash”real estate deals and intense arm twisting for preferential treatment through mundane local political machine corruption, and an organizational need to stay in place and not move to the exurbs for a new campus.