Pretty ridiculous to think that either of these guys are retiring with a loss IMO. Neither of them are that old and neither have particularly been on much of a downslide (having only lost to the #1 contender). Just because they may not win the belt doesn't mean they should just hang it up. Look at Arlovski; he was on a 5 fight win streak and has now won 2 straight.
Remember that there are much, much bigger things at stake than rankings and "legacy"... fighting is their livelihood and the way they support their families. Do you think either guy has enough money to just retire now and not have income for the rest of their lives? Opening a camp or becoming a coach can be risky ventures just like starting any business and many fighters don't have any other skill to fall back on. With that being said, no, I don't think either guy is even close to being done and will fight in the ufc at least 5 more times.