Jay, let me get this straight. If I read your post correctly, you're implying that a reg. chain and an o-ring chain will last approximately the same amount of time, if both are give the proper maintenance, correct? From what I've read here, with what I've been able to figure out, that's not it. I may be wrong, and if I am, someone please correct me(in gentle terms, pls., I'm fragile;) ), but the main reason for the rings is to keep out the harmful elements(i.e. sand, water, little Johnny's Kool-Aid......) from the interior of the roller bushings, thereby keeping the contaminents on the exterior only, thus making it easier to get them(read:clean them) off of the chain and lengthening the life of the chain. With a reg. chain, you will almost never get every thing out of the inner roller/bushings b/c it's just too small of an area get at. With an o-ring, the ring keeps the lube that the company puts inside the bushings(if they indeed DO put lube in there) and it's only the exterior of the chain that gets cleaned, where as you end up cleaning a reg. chain inside and out. I don't know a whole about this biking thing as I've just been involved w/it for just over a year, but I do know that one of the biggest things that wears a chain is grime(spec. dirt and moisture).
Once again, if I'm off, someone please correct me.