I guess I'm a bit confused by this thread. I played XI for a good long time and at cap you still were required to have a set piece to be capable of entering certain content. Most of those pieces were either extremely pricey or were a rare drop that required vast amounts of time and effort to get unless you were extremely lucky ( looking at you kote... looking at you...). At 75 cap ( before the game got really broken) if you could wear it then you wore haubergeon, byakko's haidate, Sniper's rings +1 etc. Tanks wanted jelly ring etc....

So even with horizontal gearing, everyone still wore the same thing as everyone else. The only difference being that it took so much time to grind to that point that it seemed like you didn't always need it. Make no mistake though, if you wanted in endgame content in a good linkshell that had a history of clears then you were required to enter into it with a certain amount of acc and other stats.