It seems as if most "credible" historians subscribe to The Lone Oswald theory.
I honestly have not put that much thought into it.
Back in the 70's I read Whitewash, and what the author of that book thought should be obvious.
More recently I read Oswalds tale by Norman Mailer and Lawrence Schiller
and
Marina And Lee by Priscilla Johnson,
and
they both seem to subscribe to The Lone Oswald theory.