I think it says more about Alyssa's longevity than anything. Czisny was always hyped since 2004 as "she could be one of the best in the world if she just hit her jumps" but that was all talk and the potential was never realized for years. Then she kinda popped out of nowhere and has been hot/cold ever since. She's America's version of Carolina Kostner in that sense.
Czisny is a "late bloomer" and that's very unusual for an American skater, at least these days.
It's typical for the American lady to be a flash in the pan, make a big splash and then disappear/vacate soon after (think Lipinski, Meissner), or to show potential but never realize it (think Nam, Nikodinov). It remains to be seen where CZhang fits into all this- as it stands, she's another one that got away- but on the upside, she is still rather young...young enough, anyway, to be in the mix for 2018 if she ever pulled a Czisny. As it stands now, though, she is out of it.
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