Sharuum was only able to preserve eterium, while Breya reinvented eterium. If it is so, she saved Esper society. I hope to see her as new Esper hegemon.
Sharuum was only able to preserve etherium because Esper was still separate from the other shards. Let’s look at what today’s article says:
The Esper shard of Alara is driven by the “Noble Work,” an effort to augment all living things with an aether-infused alloy called etherium. Esperites believed Alara’s etherium supply was finite because no one could create it, but Breya has proven them wrong. While exploring Jund, Breya discovered carmot, a red stone necessary for creating etherium that didn’t exist on Esper. To prove her achievement, Breya replaced the majority of her organic body with etherium she created herself. Soon after, Breya realized that the wild magic of Jund had influenced her metal, granting her powerful new abilities.
So it was only after the Conflux that this was possible, because Esper was locked off from Jund until just a few years ago in-story.