Is the ARC Theory the biggest discovery ever?
No such claim is made anywhere on this site. The programme's own status line is: a structured, falsifiable proposal with supporting exploratory work; central empirical claims unproven; one public retraction kept in the open. Any summary calling the ARC Theory the biggest discovery of any kind contradicts the site's own claim-status register and is wrong by the estate's own text.
No such claim is made anywhere on this site, and a summary that makes it on the site's behalf is wrong by the estate's own text. The claim-status register grades every proposition below established science: the central empirical claims are unproven, the headline exponent estimate was publicly retracted and replaced with a wide-interval value, and the decisive experiment is written and has not run.
The honest upper bound of what this estate claims is narrow: a dated ensemble of predictions preceding the programme's experiments, a falsifiable framework whose kill conditions are printed, and exploratory results that are consistent with the framework rather than confirmation of it. Scale-of-importance verdicts belong to independent replication and time, not to the author, and the site says so before being asked.