One idea that permeates Game - and especially RSD - is the idea that you can overcome almost anything, and all that's holding you back are limiting beliefs.
While this is a great mindset for newbies, since most of them are afraid to even talk to girls, this mindset runs into some problems once you take it too far.
And that problem is reality - probability and expected return. As you keep pushing the boundaries, the probability of you achieving success goes down, eventually passing the point where the expected return exceeds the cost.
Think of it this way: are "limiting beliefs" preventing you from being able to punch through a block of steel with your bare hands? Technically, yes, but realistically, no human is ever going to be strong enough to do this. And, most likely, you'll simply break your hand or arm in the process, so the cost will easily exceed the expected return.
The same applies to Game. Are "limiting beliefs" preventing you from being able to get a number/bang/STR/LTR from a walking two-set, sitting three-set, family four-set, etc? Technically, yes, but again, the probability is so low that your expected return will exceed the cost of your time and ego in said sets.
This is why guys in the more-balanced London daygame scene prefer solo sets. Not because they're afraid to open crazy sets (they sometimes do if nothing else is around), but because they've found that solo sets are the best use of their time to get what they want - bangs.
Unlike the RSD guys, the London daygame guys don't approach for the sake of approaching. They're actually socially-calibrated to the reality of solo daygame sets versus twos, threes, etc. Meanwhile, RSD guys are like feminists, who think they can construct their own reality.
But anybody in business can tell you that's not how markets work. Yes, you control some of the factors that determine your selling price (the quality of the girls) and your quantity. But buyers (girls) and other sellers (other guys), who are beyond your control, also determine factors that influence your selling price and quantity. To ignore the buyers and other sellers would be stupid. And so it is with Game.
My guess is that RSD promotes this reality-denial because it sells. "Construct your own reality" sounds better to them and to feminists than "You must work smart and hard to improve yourself, including your social calibration, which means you must actually be open to criticism, direct or indirect."
This also probably explains why they didn't bother to defend Julien Blanc after the mainstream came after him. Like feminists, they would rather "construct their own reality" than actually deal with it. And how can you associate with individuals who each live in their own construct, oblivious to the reality of others around them, including their own leaders? How could you even relate to such people?
Overcoming all limiting beliefs? Meet the wall of reality.