Do you have a source for those numbers? I'm curious about what % of the top-grossing apps are considered "the best" i.e. if 1% of apps are making billions but

Do you have a source for those numbers? I'm curious about what % of the top-grossing apps are considered "the best" i.e. if 1% of apps are making billions but the other 99% are complete flops, it seems ludicrous that anybody would try to enter the market as this stage.