The issue with big cocks and some not being able to take them doesn't come from their skill of taking cock but from the guy's skill to put it in. You can't blame the guy either really, he's probably never been fucked by a big cock himself. But even if he has, he can only have been fucked in the ass, and I don't know if the feeling of a big cock in the ass is the same as in the vagina because I don't have a vagina.
However, it is more on the guy knowing how to use a big cock than on the girl knowing how to take it. I'm 20 cm, rather thick, and I've always enjoyed fucking my ex girlfriend and feeling big inside her by hitting a wall or her uterus. Knowing you're getting to the limits inside her is a nice ego boost. But more than limits, it has to do with position and angle. With the right orientation and technique, you wouldn't be hitting anything inside, and that makes the experience all the more enjoyable for her. Feeling filled up and stretched is indeed a nice feeling, but feeling poked and misaligned can be uncomfortable and painful.
Same thing goes for anal. There's plenty of space inside an ass for a big cock to fit in there and be enjoyable, but the moment you start hitting walls it's no longer enjoyable. Trust me, you hit those walls again because of angle and orientation, not because of lack of space, because especially in the ass, there's plenty of it.
This is a very difficult skill to learn, mostly because as a straight guy you don't experience being penetrated in your ass or vagina, so you don't know what to change and how to improve. Feedback is not easy to give when as a girl you yourself don't know how to describe what is wrong, are shy or embarrassed to talk about it, don't have that level of trust with your partner, or just assume this is what sex feels like and think it's normal. These are already too many barriers to provide feedback. But even when a girl gets past all of them and shares feedback, the guy needs to also be able to receive feedback first, and willing to incorporate it second. You can imagine this is a lot of steps that need to happen for someone to improve. With the average number of sexual partners in the Western world being 8 over a lifetime, there aren't that many opportunities for guys with a big dick to improve so they just do what they know.
Looking for a size queen to fix this issue is like thinking more bandaids will make a boy ride a bike better and fall less. They are unrelated. The boy just needs to learn how to ride the bike first.
So we really need a change of mentality and to shift the focus from the girl to the guy. You are responsible for how you use the tools you are given (your cock) and you work with the material you have (your partner). If you only have a very big screwdriver and the bolts are just normal, it doesn't mean you need bigger bolts, you just learn to use the screwdriver carefully because the bolts will screw with either size of a screwdriver.