Chief Justice Goldberg? A SCOTUS counterfactual

I am reading Lee Levine's and Stephen Wermiel's The Progeny, which traces the history of New York Times v. Sullivan and subsequent cases and Justice Brennan's efforts to control development of that area of First Amendment law. Arthur Goldberg makes a brief cameo in Sullivan and Garrison v. Louisiana as a third voice on the Court (along with Justices Black and Douglas) pushing for absolute First Amendment protection for all criticism of government and public officials, before resigning (at LBJ's urging) in summer 1965 to become UN Ambassador and to allow LBJ to appoint Abe Fortas to the Court.

So a counterfactual (and maybe this has been written about): What if Arthur Goldberg had not resigned from the Court?

Short term, The Progeny shows that the early path of post-Sullivan defamation cases might have been different. Goldberg aligned t with Black and Douglas for the broadest First Amendment protection (beyond Brennan's actual malice), while Fortas went in the other direction, on one occasion all by himself. Certainly football coach Wally Butts does not keep his defamation judgment if Goldberg rather than Fortas is occupying what at the time was called "the Jewish seat."

What about longer term? Chief Justice Warren supposedly wanted Goldberg to succeed him as Chief. We probably do not get the insanity of the failed nomination of Fortas to be Chief. We definitely do not get Fortas' subsequent pressured resignation from the Court. Do we get a Democratic Chief in 1968 (Goldberg? Brennan? Someone else, and if so, who?), instead of Warren Burger two years later? Would Goldberg have been filibustered the way Fortas was? And if Goldberg becomes Chief, we get someone other than Harry Blackmun in that associate justice seat, another LBJ nomine in 1968 (likedly Homer Thornberry of the Fifth Circuit, who was nominated to Fortas's seat when Fortas was nominated as Chief). In either event, Goldberg lived until 1990; does he become a 20+-year Justice? (or was too otherwise-ambitious and distracted, believing he could be Governor of New York or President).

If nothinge else, does Flood v. Kuhn come out differently? Goldberg likely would have been a third for Flood on the Court, which might have moved other people. More importantly, Goldberg no longer can represent Flood, so he no longer can deliver one of the worst arguments in the Court's history.