With consumer 802.11g costing below $70 for good gear, enterprise APs still run you more than $400 with discounts: There is, of course, a price premium you pay for devices that handle VLAN switching, multiple broadcast SSIDs, and other enterprise-related features. But the difference between the underlying silicon is pretty small (or non-existent) these days. You're paying a large differential for brand, service, support, integration, firmware, and the firmware's hooks for management. And switch AP cost even more but provide more flexibility, which should lessen server-room and management costs.
Well, okay...but how is this different from the current situation with Ethernet switching (Cisco, Foundry, Extreme vs. D-link, or no-name brands)? That's just networking--the same holds true for printers (a workgroup printer from HP is double, triple the price of a consumer model), or software (Red Hat Enterprise edition vs. consumer edition), etc.
This is par for the course when talking about the difference between Enterprise and Consumer products. Those "other items" you mention: support, feature set, etc., cost a lot of money to implement, and that has to be reflected in the final pricing.
Also, take Microsoft's own WLAN network as an example--they were using consumer grade 300 series Cisco APs and it cost them significant in-house support resources to manage the large network. The reason they are looking for a WLAN switch solution is to reduce the costs associated with managing a large WLAN network--no consumer product can deal with the roaming, AAA, VLAN, IDS, Rogue detection, management, etc., etc., etc., issues that Enterprises face.
Y'all forgot to mention security. I guess it was covered under "other"? ;)
[Editor's note: Most consumer access points now feature the same security features available in the high-end enterprise access points: 802.1X and VPN passthrough, WPA, support for AES/WPA2 through firmware upgrades when finalized, etc. --gf]