As does OS X Server, but it doesn't "just work" out of the box the same way Macs do in general, or even iCloud for individuals.

For a 5-25 person SMB, there's not a full-time IT guy who could set it up. At best, there's a desktop support/printer/office manager type. At a tech company, you might get lucky (or unlucky) and one of your devs or site-sysadmins spends much of his time setting stuff like this up.

ARD is pretty weak compared to MS SCCM, and super-weak compared to something like AirWatch or Zenprise (MDMs).