The 'Candle in the Wind' singer said that programmes like The X Factor are purely "entertainment", and called television in general "boring" and "brain-crippling".
John also revealed that he turned down the chance to replace Simon Cowell on American Idol because he would not be able to "slag anyone off".
He told Radio Times: "I'm not a fan of talent shows. I probably wouldn't have lasted if I'd gone on one. I like Simon Cowell, but what he does is TV entertainment.
"I was asked to judge American Idol. I couldn't do it because I won't slag anyone off. Also, I don't want to be on television. It's become boring, arse-paralysingly brain crippling.
"There have been some good acts, but the only way to sustain a career is to pay your dues in small, s**t clubs. TV vaults you to superstardom and then you have to back it up, which is hard.
"Leona Lewis and Alexandra Burke are at the mercy of the next song they can get. Susan Boyle was an endearing phenomenon, but I fear she might not understand the rigours of showbusiness."
John went on to stress the importance of new artists working their way up through the music business, rather than exploding onto the scene via reality TV.
"I was in a band at 17, became a songwriter with Bernie Taupin and wasn't successful until we'd had six years of hard graft and disappointment, as well as great times," he explained. "I had experience you couldn't buy."