Let's face it, we don't get to check out a man's endowment right off the bat.
Exactly. How would any weak minded, submissive beta-male know who he should submit to? lol
Of course, well endowed guys will likely have more confidence with women, or maybe it's more accurate to say smaller guys are more likely to have problems with a lack of confidence. I've spoke with several big, even huge dicked guys on thevisualiser site who said they're terrible with women, suck at talkin to em, lack confidence, etc. Simply having a big one doesn't make you an alphamale. And of course, there are plenty of small and average dudes who are as cocky, arrogant, assertive, and dominant as you can get.
In pornography, especially various fetish related stuff like femdom/sph/cuckolding, the topic creator's comments ring true. I mean as a fan of this type of stuff, I do in fact feel more submissive towards bigger dicked guys. But this is almost purely fantasy. Some guys who engage in it might honestly believe it, but the overwhelming majority of us know it's all an act, all for fun, I'd say ALL the women involved in it feel the same.
In the real world, your natural order stuff is hogwash.