Paul McCartney is a living legend but cannot sing these days. Rick Astley is still doing his thing well though, he was brilliant at Glastonbury. Saying he'd "wipe the floor" with very competent, professional, modern acts just because he's a British golden oldie is nonsense though.
It's Eurovision, not a samey concert at Buckingham Palace. You have to be forward looking and forward thinking to thrive, not just "oh this slightly misogynist old dude sold loads of records in the 70s, let's send him and his leggy blonde dancers and wipe the floor with Italy's best selling contemporary singers". It ain't gonna work.