Not quite true, but I'm compelled to accept your position - primarily because of other research I've done since. However, my point had more to do with lag in principle and that one should point the thumb before the finger. I'll still stand by that.
Here is a post outlining 7 steps the user can take to fix lag client side. Specifically, if you're been playing for more than a year, you'll want to pay attention to this one. Most long running networked games (esp. MMO's) have similar client side issues.
http://ddowiki.com/page/Client_defrag
In game you can open the help manual, search for "lag" and the top recommendation to solve for lag is to lower your graphics settings.
Another reason I point this out is due to anecdotal evidence. Having solved lag issues for several friends new to MMO's, this has been the most successful approach. Not only in DDO, but other popular high-res games.
Further anecdotal evidence includes successful shutting down of background applications including torrent clients, streaming audio, virus scanners, etc..
Having shared instances with other players having lag issues I can say graphic settings and network issues can certainly affect the rest of the instance.
I said I was new to DDO, but this isn't my first MMO.
Disco + FW = Dead Gargoyles
“If at first you don't succeed, keep on sucking till you do succeed.”