Great reference. If Heinlein "abandoned it", hre did so because he didn't like it. I hate this recent practice of resurrecting dead novelists anyway. Robert Ludlum, Lawrence Sanders, and a host of other long-deceased writers seem to have left stockpiles of "manuscripts" for no-name authors to "put the finishing touches on".
Now I understand why C. S. Lewis left orders that his papers be burned upon his death.
I just went back and reread the entire postscript - and I missed something. This further damns Robinson's idea.
"I imagined Nehemiah Scudder as a backwoods evangelist who combined some of the features of John Calvin, Savonarola, Judge Rutherford and Huey Long. His influence was not national until after the death of Mrs. Rachel Biggs, an early convert who had the single virtue of being the widow of an extremely wealthy man who shared none of her religious myopia - she left Brother Scudder several millions of dollars with which to establish a television station. Shortly thereafter he teamed up with an ex-Senator from his home state; they placed their affairs in the hands of a major advertising agency and were on their way to fame and fortune. Presently they needed stormtroopers; they revived the Ku Klux Klan in everything but the name - sheets, passwords, grips and all. It was a 'good gimmick' once and it still served. Blood at the polls and blood in the streets, but Scudder won the election. The next election was never held."
Game, set, match, I should think.
Thrones, Dominations, Jill Paton Walsh's finishing up of Dorothy L. Sayers last Peter Wimsey novel, is an exception, except for two unfortunate word choices. But basically you're right: resurrecting dead novelists' dead novels doesn't work.