Of course it's well known how much money some artists make through their tours. People are willing to pay the price to see them, so good for those artists.
However, at what point will it no longer work? At some point the prices will be too high to sell out arenas. Big acts have been able to demand $1,000 or more for the best seats at giant arenas. Like so many others I can't name a single act that is active currently that I would pay anywhere near that much to see. If prices - and fees - keep going up the number of people in my camp will increase. Maybe the premium experience will be enough to offset that, but at some point demand side economics will take over.
If I can buy every single album, LP, single, and special edition an artist has ever released for less than 1/4 of what a ticket goes for - or for that matter less than just the fees for a ticket - the system seems a bit broken. Sure the live experience is different but is it worth that much?