Um, no. I say this as a holder of season tickets to the opera and as a trained operatic tenor myself. Many, many pop singers are incredibly good and far outstrip the skills of most barroom singers I have experienced.
People think they could sing Britney Spears just like her until they get behind a mic to record. Most people don't even know the cringey feeling of "God, I didn't know my voice sounded like that" after having heard their own recorded voice for the first time. Or how out of tune and rhythm they actually are.
So no. Everybody thinks they could sing the typical pop song, but I doubt that they could.
Pop music is a commodity, and as any commodity it's pricing/value is basically a race to bottom.
my point was that singing entertainment (e.g., pop) is widely available (someone sitting near you right now can probably sing well enough to be entertaining), so not scarce. you can find millions of decent takes on pop songs on youtube.
and further, the level of passable entertainment is low, both because plenty of people can sing passably, and because enjoyment of the music comes not from admiring the skill but mostly from other factors.
take pop music (of all sorts) for example. the money that pours into it is puzzling if you consider the music on its own merits. the melodies are catchy and the lyrics too, but no one really considers it high art. any barroom crooner could sing and play it.
(in fact singing is probably the most accessible and widely distributed art form. we're all born with the instrument and a little practice is all that's needed for passable entertainment.)
so why do pop stars make so much money? it's simply not scarcity that drives the price. it's fashion, or culture, or whatever you prefer to call it. it's the need to forget our troubles. it's our secret hopes and dreams routed through a channel for bonding with our fellow man. that's what we're paying for.
and we'll likely always pay for it. but whether the marketing machine of yesteryear can continue to maintain a stranglehold on access and taste is really the open question.