Aside from cliches about The Patriarchy and all the other transiently politically correct tropes that substitute for real thinking, the hard fact is that most people are insecure. And insecurity paralyzes pleasure. For beyond-the-norm sexual experiences it's generally necessary for one person to act as the catalyst; such things almost never occur spontaneously. In general, for a MMMMFMMM type of experience, a confident man has to be the catalyst - and that's a rare animal indeed. I can say, from personal experience, that multiple men with one (or two) women can be astonishingly satisfying for all concerned (and indeed, quite addictive) but sadly insecurities will tend to relegate such things to the realm of fantasy. We live in a world rich with potential opportunity, but in general we are too fearful to do anything other than what we've already done a thousand times before and are bored with, but cleave to for its predictability and safety.