The OP is asking, what will happen when a generation of human are indulged in useless idols.
Then you continue to describe an industry out of useless idols and their fans...
Hack, I am not surprised by this type of apparently startlingly myopic vision of human society. It seems everything is just for profit. No matter how stupid the thing is, if there is a chance for profit, then go for it.
In the end, who can answer the simple question: Who create the value to drive the profit?
Buy an ad and your customer might remember it. Create a meme and you live forever.
There is a reason Bollywood is a more profitable "industry" than Hollywood, and it's not because their product is better. It's because their society actually nets a profit from production that they can then spend on leisure.
If our best and brightest young children become internet celebrities because it made good sense, then there won't be anyone to keep the gears grinding.
Worse than that, on instagram you're still the product being sold even when you're then one being followed.
Whether you like it or not, entertainers produce goods or entertainment-related services within an economy. That's the definition of an industry.
So do you also support not educating a vast majority of children because if everyone aspires to be a white collar worker, where will we get our janitors and garbage men from.