Same can be said about the last batch of 'sonograms' (Meissner, Zhang, Flatt, Nagasu). None had the longeivity that Ashley had.
But of the U.S. ladies you name in opposition to Ashley Wagner,
Kimmie Meissner is a year-and-a-half older than Ashley. Meissner did not hang around very long competitively because of injuries. Meissner came up to seniors before Nagasu, Flatt, Zhang and Wagner. Also, let's be honest that Mirai Nagasu ended up having some serious comeback longevity and ultimately her own modicum of success. While I agree with the gist of your post, let's please understand that Nagasu, Flatt, and Zhang are all contemporaries of Wagner's.
This U.S. group of 'sonograms' which includes Wagner, were on the U.S. scene before the whole Russian 'baby ballerina' BS rose up like a faux phoenix. Ashley Wagner indeed was once an understudy to two prized U.S. 'baby ballerinas.'
Further context: Ashley Wagner is only about a year and two months older than Rachael Flatt. And Wagner is two years older than Caroline Zhang and Mirai Nagasu. At 2007 U.S. Nationals, Nagasu and Zhang at ages 13 (soon to be 14) were 1 and 2 in junior ladies, while some fans likely forget that Ashley Wagner at age 15 (soon-to-be 16) placed 3rd behind Nagasu and Zhang. The latter two ladies were heavily touted and over-exposed by U.S. fed and the media, immediately after that competition. Meanwhile, Ashley (as 2007 U.S. junior ladies bronze medalist) would eventually become more competitively successful in seniors, despite the fact she was never seen as having Zhang's and Nagasu's level of overall talent.

Nor was Ashley ever singled out as charmed U.S. fed favorite in the way that Rachael Flatt was for a brief period of time.
Ashley Wagner had her own unique measure of talent as a figure skater, even though it was not overly shiny and outsized. Therefore, Ashley learned that she was the person who had to nurture and maximize her talent. She had to believe in herself and convince renowned coaches that she was worth investing their time in. And even after succeeding against the odds, Ashley had to continue proving herself vs every new U.S. fed fave who shined bright like a diamond. Ashley had to endure and become the sapphire amidst sparkly shooting star diamonds.* Ashley had to pull herself up by her bootstraps and Ash Swag herself to the top by dint of her own desire and hard work. In remarkable fashion, Ashley accomplished these feats and then some by taking her career into her own hands after being written off by TPTB as the also-ran 'almost girl' circa 2010 U.S. Nationals.
*
"A diamond is about the brilliance, fire and scintillation. It is about the sparkle and the light that gets reflected back to the viewer's eye. A sapphire however is more about its inherent body color. It is about looking at the beautiful color and enjoying it for what it is."
Some people have never enjoyed Ashley Wagner for who she is, for her beauty, for her endurance, and for her stellar, self-made career.