As stated, I think the Zoidac will end up like Jack the Ripper. In another 100 years everyone will still be speculating about the "known" suspects. I do not believe it is any of the "known" suspects, although I have at one time or another seen very convincing arguments about most of them.
After the identity of BTK was revealed, I became convinced that that Zodiac was probably a very similar story. In that I mean that while everyone is looking for the freak, the stand out crazy, Zodiac was likely simply going about his life which likely included a nuclear family. At least when he wasn't murdering people.
Also like BTK., he liked toying with the press and LE and I think would ultimately want his identity known when he died. However, I don't think his family would have wanted it known.
It's one thing to accuse a stepfather or a bio dad that was never part of your life, of being a sadistic serial killer. It is quite another, IMO, to admit that your dad, the man that raised you and that you loved, is one.
After living 58 years of my life without knowing I was adopted I recently had a phone conversation with the man that is listed on BC as my bio dad. He means nothing to me.No offense to him, he says he never knew about me and that may be true. I am not angry at him, he just means nothing. IF I were to find out he was a serial killer? Other than wondering if I might have inherited some of the "crazy" I cannot imagine it really being all that difficult to accept.
However, my "dad" the man that raised me, loved me and taught me so many things about life? The man, long since dead, whose examples of honesty and integrity I still try to live by? It would devastate me to find out that he had ever stolen $10 bucks in his lifetime, much less killed someone. Much less been a notorious serial killer.
I find it completely believable that the real Zodiacs child or children covered up whatever "proof" he left behind. Based on the timing and the age estimates, particularly if the Police Officers estimate was close he would almost certainly be dead by now. I don't think we will ever knonw the truth.