If bandwidth is cheaper, the rule is to flatten your networks out. This would link to the WAN through one special switch designed to provide wide-area connections for the community. Where the number of workgroup switches prevents full meshing, a second tier of switches of limited size can be used to create the network. Such a LAN has fewer devices than the traditional structure, and lower latency because there's less handling of packets. You'll note that I said WAN connections would be made through a special switch.
Switches are cheaper, and routers are best at managing congested links and finding alternate paths.
Alternate routes are key to reliability in a complex public network like the Internet, but most company networks won't have many alternative paths to choose from. That leaves congestion management to justify conventional routers. Fiber bandwidth is high in reliability and usually cheaper on a unit cost basis, meaning that a megabit per second costs less on a modern fiber connection than on old copper wires. Users don't really spend less in absolute dollars, they just get more bandwidth for what they spend. If that's the case, the network will have more capacity available, congest less, and need less traffic management.