Speaking from experience, Reason #2 (The Ouch Factor) is actually the most important, if you're already of decent size. If one was average sized and wanted to get bigger, that's one thing, but if you're already large you're probably just going to increase pain by going any bigger. Sure, a few may be able to tolerate (and enjoy) it, but you're going to decrease your market overall. Your ego may increase, but I'd rather not leave my girl sore for days.