fantasy scenario 1
Mummy? What is that man singing about?
He's singing a song about the fact that the Queen has made a law that nobody can sleep in the kingdom until she learns his name, but you see . . . (Here's a synopsis of Turandot. "Nessun Dorma" -- roughly translated as "nobody is sleeping" -- comes at the beginning of the third act).
Can we watch this opera some time?
fantasy scenario 2
Some accomplished musicians, including instrumentalists, get the idea to enter these kinds of contests with the hope that Simon and the other judges might give them a chance. They can all make sure to mention their day jobs as their primary occupations.
fantasy scenario 3
People start to realize that singing by really using a trained voice and not depending on a microphone for projection can be a very powerful thing. They might want to do it themselves. Then they might start to think of what they previously referred to as "talent" as a matter of training and discipline, and they might even start to move away from using amplification altogether. Modern churches might once again be constructed to have real acoustics rather than have expensive sound systems, and the ever-growing number of people who will go out of their way to hear excellent singing will choose powerful trained voices over powerfully-amplified ones.