The thing about lists like this is that as they are updated, the real greats always stay on the list, always near the top. The lesser “greats” will mostly fall away and be replaced by another crop of the latest fad performers.
A perfect example is K-Pop boy-band star Jung Kook. Will he still be one of the “greatest” in 10 years? I doubt it.
And how about the one (#200) who is praised for “heavily incorporating Auto-Tune — not to mask her voice, but to instead emphasize the nuanced texture of her performance, which fluidly shifts from ferocity to playfulness to sorrow.” Cut me a break. Auto-Tune is a crutch for mediocre singers.
Auto-tune was a useful tool to save time and money in the studio. When a good singer flubbed a note, they could fix it without re-recording the whole song over again, straining the singer's voice and increasing the likelihood of more bad takes.
It has since been overused to make bad singers sound good, or to add those horrible chipmunk or robot voices.