I am also ultimately bored of topics of pure speculative nature.
The fact that, ironically, the first sound recording device was created a decade before Liszt passed away and so could never reach the average people's homes for yet longer time, is like a joke by God himself. If we'd get to hear Liszt play, it would probably be a disappointment no matter what, looking at the level of divinity that people have raised Liszt to by all the wild stories about his playing. He's a legend, leave it at that. His playing was probably supernatural, but there's absolutely no need, nor interest, to speculate whether he was the ultimate best pianist ever to walk to Earth. This kind of talk just sounds to me like a whole lot of people are interested in wrong things, missing the point of what Liszt is, as a human being, a composer, an artist, a pianist, a personality. There's something called sports for those of us who want to define the peak of human physique and what can be achieved by it.