We have had this for years in Montgomery County. Let’s say a really nice neighborhood is planned. Fine. But to get all the permits, there has to be a % of low income/HUD housing available. So, you have the “higher price” single homes, the town home section (regular priced) and within the town home section.. a percentage of lower income. That’s why about 20 years ago or so, there was a Monkey county escape to Frederick and Carroll County. A real estate agent I knew from school always knew the Montgomery Co residents because she would show them a house and they would ask, “Where is the HUD section?” At that time, it didn’t exist there.. not sure if it still does.
I grew up in Montgomery County. I have always noted when coming back to visit, how many previously nice middle class neighborhoods have changed. I also noted how more distant suburban areas such as Frederick have really grown. We can put two and two together and figure out why this happened.