No, these are not *automatically* off-topic by virtue of using consumer-grade solutions.  See http://meta.serverfault.com/questions/2713/whats-off-topic-anything-in-a-home-setting-or-anything-that-was-designed-for - MikeyB's answer actually has direct discussion of consumer routers.

But that doesn't make any of your points any less valid.

 - If it's home use or has a strong odor of home use, it's off-topic.

   Any questions with these tags deserves scrutiny!  Read between the lines on the question, and if it doesn't have the texture and flavor of a professional environment, then bring that up in comments or simply vote to close.

   Looking back in the tags we've certainly [got][1] [examples][2] that are clearly professional cases - as well as a [bad old poll question that should be closed][3], which has several of our users (including the #6 all time user and a community moderator) stating that they do (or did) use these solutions in the workplace.

 - Even if it is on topic, if it's clear that the asker is using the wrong tool for the job, telling them so is very much a valid answer - even if it's not the answer they want.  I'll most likely upvote it.



  [1]: http://serverfault.com/questions/322824/slowest-wireless-client-dictates-the-connection-quality-of-all-others
  [2]: http://serverfault.com/questions/28994/inexpensive-reliable-captive-portal
  [3]: http://serverfault.com/questions/32999/does-anyone-use-dd-wrt-openwrt-etc-at-their-office