Pearl Jam tried to do something about it 25 years ago but their monopoly is too entrenched. They gave up.
https://faroutmagazine.co.uk/pearl-jam-war-with-ticketmaster...
does ticketmaster monopolize small venues, as well?
maybe those venues could also sell streaming access as well as in-person viewing, to attack ticketmaster from 'below'. Other than Pearl Jam (and Prince, RIP), the big concert attractions seem to be happy with the current ticketmaster situation.