Didn’t Barry Goldwater revert to Liberalism in his latter years? Was Barry just conning us in his former years?
On social issues, yeah, he took an unfortunate left turn in his old age. No, I don't think he was conning us in his former years.
If you're comparing Trump to Goldwater (an offensive comparison, if you ask me, but leaving that aside...), let's take the comparison all the way. After his (partial) turn to the left, do you think that (age aside) the Dems would have run him? Would he have had any credibility as a liberal candidate in a Dem primary? If not, then why should Trump have any credibility as a conservative candidate in the GOP primary?