That's easy.
USCIS were forced to act by the judgement issued in this United States Court of Appeals, Ninth Circuit case
Poghos KAZARIAN, Plaintiff-Appellant, versus US CITIZENSHIP AND IMMIGRATION SERVICES, a Bureau of the Department of Homeland Security, Appellees.
Kazarian actually lost the appeal. Although the judges ruled that USCIS had erred in how they interpreted the law, it was ruled "harmless", since Kazarian could still not have satisfied three criteria as required for EB1A.
The fall out from the case was the need to develop a two-stage adjudication process. In theory, it should have made it slightly easier for EB1A/B applicants, since the actual evidence for the criteria became less rigorous. In fact, because it has made the decision more subjective, it has had the opposite effect.
Here are AILA's comments when the new rules were put forward for comment. It discusses legitimate concerns that USCIS had overreacted to the Kazarian decision.
There was never any accusation of abuse in EB1A or EB1B, either before or after Kazarian.
It is a complete red herring wrt to the title of this thread.