I was born in '76, and “Elvis is still alive” has been a running gag for my entire life though less so over the last two decades. I remember in the 80s seeing tabloid rags like The National Enquirer (remember when they weren’t just a celebrity rumor rag?) with headlines about Elvis living his best life as a regular person.
I have a difficult time believing one of the most famous people to ever live could just vanish or melt into obscurity with disguises. They had neither the makeup nor surgical technology in 1977 to render someone completely unrecognizable without turning them into Jocelyn Wildenstein. Hell, we don’t have that technology now. The man had a public funeral. 30,000 people walked past his open casket.
The alternative would be to live more or less alone in an isolated place and never ever leave, with just one or two people to acquire everything he needs for several decades and not ever say a thing about it to anyone.
One of the conspiracy theories is that he was abducted by aliens.
In the hitchikers guide to the galaxy he appears as a bar singer on another planet but reveals he went on his own accord.
With alien medical care it is quite likely he is still alive.
The Soviet Union did make attempts to hide Hitler’s death from their public. It was part of their disinformation effort to suggest the United States/Great Britain helped Hitler escape. i.e. Those pigdog capitalist are all fascists at heart.
I actually knew a woman who was a true believer. It was about 94? I don’t remember what set her off, (she seemed pretty average up to this point) but she suddenly announced to me something like she couldn’t wait 'till Elvis showed up, that would show them all. I just sort of stared at her and stuttered erm yeah.