You can look at it that way and I would somewhat agree but there is another way to look at the situation.
If Des Moines doesn't make it easy to get downtown and let's say WDM does than you may see some companies relocate even more to the burbs. I've been involved in planning relocations and this is one important consideration that businesses look at before they move. I can tell you that we lost a lot more people when we moved them downtown than we did when we moved them out to WDM. The only complaints we heard when we moved some out to WDM was lack of a nearby bus.
You also have to consider the non-business factor. I'm more likely to seek entertainment downtown if there is an easier/faster way. Right now I drive out to the west mix-master to get onto 235 and head downtown. If I didn't like the downtown so much it would be a lot easier for me just to head out to WDM for my entertainment. Same can be said for shopping, farmers markets, outdoor recreation, etc