At the risk of stating what seems to me to be the obvious, and probably offending someone; web based business apps are overrated and oversold.

If the users are all on the same LAN and there is significant data entry (orders, inventory, etc); then client/server is the only way to go. Web applications in this scenario don't add any business value, and actually slow down getting business done. By analogy, it is sort of like adding 21" wheels to your SUV. Doesn't go faster, only makes you feel better. Maintenance cost are higher too, as the tires need to be replaced more often and cost more.