Why did Edina become wealthier than other first ring suburbs like SLP? Other TCpkannig questions inside...

I'm really getting into historical planning on the Twin Cities and looking for graphic-heavy materials.

I read recently Edina had the second wealthiest zip code in the state, behind Oromo. How does this jive with places like Plymouth building nothing but 700k+ houses. Wouldn't anywhere new be more wealthy than Edina?

Why do suburbs refuse to use a grid-style road network? For example, it seems like new developments go up on roads with ditches, which makes the existing road seem really dumpy compared to the new buildings, and the after affect is the buildings are now really far back from the road when the road is upgraded.

If the twin cities is so progressive, why are most suburbs still building strip malls and cul de sac style of development?

What's the best twin city development website I should check out for history?