Depending on what one means, it very much can be and is accurate. I am not making any claim that Ashley will 'never' beat any skater nor am I claiming Carolina had consistency in her career. But even if Carolina had also never medaled at Worlds I would still say Ashley's not in the same class her. Simply put, Carolina Kostner has among the best skating skills of all time. The quality of her edges, in particular, are truly awe-inspiring, as is her speed across the ice. Her artistry and connection to her music were also, at least in certain performances, at the very top of the top of what can be done. And I'm not really a Carolina uber, either- I view these things as objectively true, at least the bit about the skating skills. Carolina's jumps are also much bigger and stronger than Ashley's. She can fully rotate a triple triple 90+% of the time and she rarely if ever two footed her landings, something Ashley still does with alarming regularity.
With that said, in terms of their competitive records, they're not in the same class either, at least not yet. Consistent or not, Carolina has medaled at Euros every year since 2005, including 5 gold medals. She's medaled at Worlds 6 times. She's medaled at the GPF 4 times.
Even accounting for the fact that Ashley has had a shorter career than Carolina, her record doesn't even approach this. She's medaled at the GPF twice and won Four Continents once. That's 'it' in terms of major medals.
So right now, no, I don't think they are in the same class, and I don't see any point in pretending they are. Liking Ashley won't make them so.