Welp they didn't get the save stuff in it seems, time to start all over.
Viewing post in Smashing Simulator Idle comments
The change hasn't happened yet. Someone else put up a tool to be able to export all the itch.io save data, though, for import whenever the change does happen, that is worth trying. https://crocmiam.itch.io/itch-localstorage-export-import