Maybe you're projecting your own nervousness/awkwardness onto them, or possibly lacking the requisite effort yourself.
I'm almost the same age as you - look slightly younger - and I've seen roughly half the girls you've reviewed. Though I wouldn't "rave" about any of them (and I honestly don't recall anyone else raving about anyone on that list outside of Andrea and Ella who I've never met) we seemed to click just fine.
We are on the younger end of the age spectrum and if you believe the (highly subjective) polls, we make up a very small percentage of the overall "hobby" (stupid fucking term) crowd - most are well into their 40's and beyond.
There's often a moment of trepidation when I walk through the door. I see them sizing me up, as anyone would when letting a stranger through their door, and I'm always keenly aware that I'm not what's expected.
Being younger is one thing, and if by extention you still have the good looks, physical fitness, playful charisma and exuberance that usually comes with youth, then maybe you find yourself competeing with the perpetual myth that guys who can get laid elsewhere don't do this. You know, that 'what the fuck are YOU doing here' look?
Are you a cop? A social pigmy? A con? Just a plain fucking weirdo? Most might scoff at this suggestion, but maybe she realizes that YOU are out of HER league. Cause let's be honest, the majority of escorts are not drop dead knockouts, but rather, while generally attractive, relatively average looking - that would at least apply to 4 of the 8 on your list.
Additionally, if she's worth two shits as an escort she has some mind to want to please you; this is after all, at it's core, a customer service position. And whatever preconceived notions she has about men of different age groups, (financial stability, likeliness to repeat, lack of/wealth of experience, higher/lower sex drive, greater/lesser emphasis on GFE vs. bouncing off the walls sport fucking, more/less maturity, different sexual proclivities etc...)may cause her to at least think she has to switch up her game plan, and may throw her for a loop.
I hate to go all Freudian on it as reading minds is just taking shots in the dark (FUCK YOU Freud!), but I think when you don't fit the stereotypical "hobbyist" mold it's fair for them to be internally asking themselves questions relative to their safety and/or how they should interact with you.
Pushing all that psycho babble aside, the best way to remedy this (and I sometimes fail at this myself for lack of effort) is to not put it all on her shoulders to cut the tension in the air.
Nervousness/awkwardness can be contagious for one thing. You ever see someone ELSE in a situation so uncomfortable that it made YOU cringe? That's what I mean - contagious.
It's easy to say that it's HER job to please you - and it is. But just like calling up Verizon to bitch about that bill they overcharge on every month, your attitude dictates the service you recieve, and can mean the difference between them going the extra mile to getting what you want, total indifference, or politely (or flatly) being told to go fuck yourself.
If you lighten up, usually she will to. It's ok to gush over her a lil bit - tell her she's fucking hot. No matter how much you think her head may be gassed up already, they never get tired of hearing it, and honestly, most women are so fucking self conscious to begin with, it can never hurt; regardless.
Tell a joke or a funny story, self depricate a little, or if you are completely destitute of personality, I dunno, find a way to slip on a bannana peel or something - laughter cuts the tension like nothing else. Once, I just casually enquired how much extra it would cost for her to smile, to which she laughed and couldn't wipe the smile off her face henceforth. It can be that simple.
Just sayin, you don't always have to just accept incompatibility or any other excuse for lameness, you can take the initiative. Pretend you're the ho and she's your client if you have to. Work the room. It beats laying there like a bedlump, silent in your discontent, and subsequently pondering why yet another one let you down.
