Some artists want their concerts to be accessible. Not every creator is in the maximizing profit mindset.
If artists really care, they would do more than lip service (some do!). When they don't, the message is clear. They might care, but they care about money more, because let's be clear, brokers buying out a venue within a day that might take a few months to sell out is good for the artist, promoter and venue. They get to offload risk to a broker, for the cost of possibly some more money in the long run, and they get all their money up front and can do what they want with it for that time.
"Correct for your show" is what I'm talking about. It's realative based on what your goals are. If you want to make sure fans get cheap tickets, you make sure supply isn't too far under demand. That can be adding a date, or playing a larger venue. That's risky, because if you misjudge demand, you might actually lose money (based on venue minimum costs).
So, artists and promoters like to ensure they are sold out whenever possible. To achieve this, they play it conservative, but that leaves value on the table. Brokers capitalize on this. If the artist or promoter was more willing to increase supply and take that risk, fans would benefit. Usually, they aren't. Sometimes, they are. Kid Rock and Garth Brooks are notable here. Garth Brookes will play a venue three days in a row, twice a day. Kid Rock might just book 6-7 days.
That's not a music culture I'd want to be part of.
I assume they pay people that are good at this to do it for them.
> they should only play large venues (which Live Nation controls)
Not all of them. Most, but not all.
> And if they were mainly concerned about money (which some are) then they'd only play the largest cities every year.
For the most part, I think you just described the concert industry as it currently exists. Usually, the only thing indicating whether an artist will book theaters, arenas or stadiums is how likely they are to sell it out. Only the biggest artists can do stadium tours.
How would you design a system to do this? All of them have a ton of flaws, but I have yet to hear a system that can beat a market.