Trusova is not a Moscow girl. She is from Ryazan, a provincial Cinderella of sort (like a Zagitova). She started skating with the less know and less skilled FS coaches. And probably never took lessons with choreographers or dance teachers at her younger ages. This is noticeable, tbh. But we see her quickly getting better!
Kostornaya on another hand is a Moscow girl, she was exposed to the great skating coaches at the very young ages. Kostornaya and Shcherbakova are big "products" of Sambo-70 school.
Shcherbakova started with a kids coach at the same Khrustalny ice-rink and when she start showing potential she got into Eteri group. Nothing changed for her, just a different schedule and different kids and coaches on ice sessions.
As for Kostornaya, she is also Sambo-70, just skated on different ice-rink in Moscow before Eteri. Alyona's grace, balletic posture and elegance is a great example of what Elena Tchaikovskaia is famous for. Tchaikovskaia preaches a "balletic approach" to figure skating. Tchaikovskaiai has some serious academic degree, she is Balletmaster. They build a beautiful training facility in Moscow for Elena Tchaikovskaia. Alyona is not personal student of hers, but Tchaikovskaia is not a very hands-on coach lately, she is more of a strategist now I was told. She taught dozen of teachers and now they coach kids on Tchaikovskaia's ice rink under her supervision. Maria Butyrskaya was one of the latest personal student of Elena Tchaikovskaia. That's where Butyrskaya's elegance and lines come from. Although Alyona's grace is better, imho. Butyrskaya came to Elena Tchaikovskaia only later on, before that she was with Viktor Kudriavtsev, he is the one who gave her a big powerful high-amplitude jumps. Alyona Kostornaya reminds me Butyrskaya in many ways. But I repeat: Alyona is noticeably better in her lines. Probably because she was just exposed to Tchaikovskaia's skating techniques and her balletic approach a bit earlier than Maria.
I was told that Elena Tchaikovskaia is the one whom Eteri really listens to and values her opinion. Tchaikovskaia herself kinda send Alyona Kostornaya off to Eteri so she would be given a more personalized attention there on Khrustalny ice rink. Like I said already, Eteri and Tchaikovskaia is the same Sambo-70 school. If someone wants to accuse Eteri group of being a "factory of mass-production" you are barking at the wrong tree. Eteri just picks the 'la crème de la crème' (creme of the crop), the real mass production is other coaches of Sambo-70 who teach kids all the basics. Kostornaya and Shcherbakova skated at different Sambo-70 ice rinks and probably just showed some promising potentials to their coaches, so they offered to go pro and switch to Eteri, and Alyona and Anna (and their parents) decided to give a FS career a shot. So both girls came to Eteri with already very strong basics. Although sometimes Eteri picks girls from provinces too (see Lipnitkskaya, Zagitova and Trusova) and they enroll in Sambo-70 school, but so far Eteri never poached students of other Moscow elite coaches.
I found an interesting video. I guess, we need to thank Elena Tchaikovskaia's talent for Alyona's elegance. I mean just look at the building Sambo-70 build for her 10 years ago. Alyona Kostornaya grow up there as well. And watch the spins, Vaganova backs, posture and hands of those very young girls! And how many of them on the same ice simultaneously:
https://www.youtube.com/watch?v=tLivSWzR5Jk
This IS a factory. Tchaikovsaia is probably a big FS influence in Sambo-70 school. Eteri is just the tip of spear of their FS program. Eteri team giving a personal attention only to the most talented ones, but real mass-production is done in Sambo-70 by hordes of other coaches and Tchaikovskaia is supervising them. I google-translated the description under this video: "
Elena Anatolievna Tchaikovskaya created not just a school, but a whole organism, where children are given not only sports education, but also develop artistic taste in athletes, teach art history and theater history. About 280 children and adolescents study on a regular basis at the school. In addition to the sport of higher achievements, the school also has a sports and fitness figure skating group for children, teenagers and adults." She talks in video a bit politically about feminism, family, about educating little girls properly, giving all of them a good basic FS education en masse and developing a good artistic taste. She wants to spread her school to all provincial regions too, she worries about health of the nation. She says even if kids won't become champions, they still would be aesthetically fulfilled, because FS is art, music, health and harmony. She says they need to educate and raise young ladies who understand the value of health, art and family. She says they raised already a decent amount of Worlds and Olympic champions. (Prolly referring to Butyrskaya, Medvedeva, Zagitova, Liptinskaya and some of her earlier students in the 80s and 70s). This youtube channel is titled "Union of women powers". Seems like there are a lot of relatively young (like Eteri age) coaches on her ice rink too.
Short promo of that ice-rink where Alyona Kostornaya grew up:
https://www.youtube.com/watch?v=4Vp_H4b3jbA
Clinic on StepSeq of juniors would be nice too. 
). If ISU will support diversity and inclusivity in our sport it would be better for FS in general and would help to ranking and viewership to go up worldwide. And would attract more sponsors. Every girl and boy on the ice rinks out where will be looking up to the skaters on Worlds, GP and Euros and will be picking the favorite by the personal taste AND by similarity to herself/himself or by something he/she can relate to. People are very different and diverse around the globe. We all are different, and we all want to see the same diversity among top skaters too. Some can be more balletic, some can be less refined, but amazing jumpers and has decent sliding skills. Pick your poison. 
so I have always thought her a fair person.
