The two laws of space explain the shape of edge city. The developer's rule of thumb is that there must be one parking space for every employee. No trees, no lawns, no sidewalks. The right ratio at the least expense. And that's why lots of development looks just like they do.
Edge cities are highly competitive with one another and hassles lead to exit.
However, the pressure to increase density does lead to agglomeration effects long before the critical problems of congestion override the benefits of higher density. This is the cheapest development, not necessarily the most profitable. Rents are low and if land is expensive, the developer will go bankrupt. To increase revenues to cover higher land cost, building must get bigger. But since developer must increase parking to match increase in building size, ultimately he must provide parking structures rather than parking lots.