Any article that states that revenue sharing has been declining in 401(k) plans is stating the obvious. Like with a dying business or organization, you can see it a mile away. Revenue sharing has been dying since the day that the Department of Labor (DOL) implemented fee disclosure regulations.
While people point out that the end was a result of so many class-action lawsuits especially the ABB/Fidelity lawsuit, I believe that fee disclosures killed it. The reason I think it killed it, was because fee disclosure finally lifted the veil on a big secret, how much certain third-party administrators (TPAs) pocketed in revenue sharing. I grew up in the business when TPAs would tell plan sponsors that using exchange-traded funds or index funds was more expensive because they ignored the costs of revenue sharing and the expense ratios of revenue sharing paying funds.
Revenue sharing payments will never be fully eliminated, but I believe it will be the 8 track tape of the retirement business.