The houses planned in the example I gave started at $400k at the time of planning, with the nicest units going for probably close to $700k especially if you took all the builder options.

Who said anything about low-income housing?

There are some unspoken things you may have to pick up on here. When people start "worrying about property values" that is standard code for something next to them being built/used for lower income people than them.

They were probably worried their 1980s houses next door would look bad in comparison to the much newer and modern houses going up the next neighborhood over.

correlation != causation.

Also, the residents were probably interested in increased property values, just like all home owners are.

Yes, take heart that the demographic characteristics of the guy that mugged you only correlated with criminality. The cause was probably systemic racism or the cishetereopatriarchy or hunger caused by food deserts.