The link you provided is behind a paywall making it unreadable unless payment is made to sign up to their subscription but I think the point you made has been noted but the claim has been disputed by some and dismissed by others:
Nasdaq ArticleI have to say there is big difference between what Vitalik Buterin stated citing data suggested a reduction in 0.2 energy consumption as a result of Ethereum moving to Proof of stake and that actually happening. There is no evidence there was any increase or decrease in worldwide energy consumption as a result of Ethereum abandoning their proof or work set-up.
When those mining farms, businesses and individuals stopped mining ETH (after it moved to proof of stake), they switched over to mining any other proof of work crypto they thought would be lucrative and that process in itself would not facilitate any noticeable drop of energy consumption on a global level.