St Helens – who lost to Warrington on Friday – are the most successful club in the Super League era, and were champions four years in succession between 2019 and 2022.
But McManus, who has been owner and chairman since 2002, said that in the past four years, clubs had suffered “a £30m-per-year downturn in the financial performance of our sport”.
In 2022, the RFL and Super League realigned, having separated in 2018, but the sport has been grappling with financial issues.
Earlier this month, the RFL reimposed salary cap restrictions on Salford Red Devils amid a protracted takeover and issues with wage payments. The game has also suffered from a fall in the value of media rights deals.
McManus said during his precious tenure at the RFL, Wood “had negotiated four broadcast deals, each of which doubled in value that of its predecessor”.
He added: “Each year the RFL broke even or was profitable, and each year the central distributions to clubs increased: heady days indeed.”
McManus criticised a fixture between the England’s women team and Australia in Las Vegas earlier this month, which ended with the “national humiliation” of a record 90-4 defeat for the Lionesses.
“Unsurprisingly, no-one assumed responsibility for the insane decision to hold this fixture and thereby destroy the hard-earned confidence and exuberance of our girls,” McManus said.
The RFL declined to comment.
On Friday, the governing body announced a new interim board following the recent series of resignations, saying that it had “worked closely with Sport England to ensure steps taken are acceptable” and “therefore avoiding any immediate risk to funding streams through non-compliance”.
Johnson had resigned after nearly six years in the role amid a revolt by some Super League clubs who had wanted him to stand down.
The chairmen of Leigh Leopards and Leeds Rhinos then issued a joint statement referring to “a growing amount of unrest over the direction of, and some decision-making of the RFL”.
