The Japan Sumo Association is essentially a reactive, rather than proactive, organization.
Through the ups, downs and various scandals of the last few years, the JSA's standard modus operandi has been to avoid making moves until public pressure essentially forced its hand.
Even then, measures taken or rules implemented have been either piecemeal or just lip service at best. When newly established committees present their findings, they are normally "taken under advisement" and rarely acted on in any significant fashion.