Frank would be a lot closer to bizzaro than a true Pope could ever be.

This has been discussed & all the sources noted  quite a few times in the past. Have u never seen any of the topics?

Never seen it , now that I now what you're talking about I'll look closer next time, but I would have to disagree with your position, the logical conclusion is the see is vacant

 the following makes sense to me

We believe that Cardinal Siri was elected Pope and unlawfully forced to resign - thus invalidating the “elections” of John XXIII and Paul VI.  But his failure to oppose the apostasy, stand up for his office and denounce the Antipopes in the decades following those fateful days preclude Catholics from holding that he remained Pope in the decades following the 1958 and 1963 conclaves.  Cardinal Siri may have been paralyzed by fear, uncertainty and confusion about his status and what to do about it; nevertheless one cannot recognize that he remained Pope in the years following his elections because, at least in the external forum, he did not stand up for his office or oppose the Antipopes.*

Cardinal Siri died in 1989, I think that's what he means.