You're right. For Joe Average, it makes a great desktop if they don't need to change anything. I think we are at the point where configuration takes some skill, but the user experience is just fine.
I've got my senior citizen mother using Slackware. She doesn't understand much of anything about computers, or viruses, or pretty much anything your average 15 year old would get about computers, but the interface is _still_ easy enough for her requirements (lolcats, email, reading news/recipes)
If she actually needs to change anything, it is past her abilities and she has to call me. She had to do that under windows, though, so no difference to me, + the added bonus that I don't clean a pile of malware off it every time I visit. Getting her on linux has cured a long standing headache.