Reality show winners / runners up with long careers?
If we are not sticking to the UK, American Idol has produced a ton:
Kelly Clarkson (won 2002)
Jennifer Hudson (contestants in 2004)
Adam Lambert (runner up 2009)
Benson Boone (finalist 2021) - early days but not likely to go anywhere soon.
Beyonce, Nicole Scherzinger, Cardi B, Carrie Underwood were all reality show contestants, Christiano Siriano did very well off the back of project runway, Emma Stone won a VH1 talent search competiton
Jamie Laing from Made in Chelsea has made millions off Candy Kittens, Harry Styles, Susan Boyle, Jane McDonald, Alison Hammond, Lee Mead .....
There's bloody 100's of people who got there shot through relaity TV or TV talent contests that have gone on to be highly successful household names.