Why? Many artists like it. It is like the farmer, they are better off with a long term deal than with one, that is negotiated in a daily basis. It is mitigating risk.

That the selling price is double of what is the buying price, this risk is then carried by ticketmaster. They have to sell the stuff. That is their job.

For the consumer, well, we feed many mouth. Just as many mouth feed us.

(in corona times, there were some practises that are critizable. but it was a exceptional time, where everyone was keeping the money at bay.)