I would disagree that they strong arm venues into exclusive agreements. If I owned a concert hall or arena, signing an exclusive agreement would be an easy decision. Have your tickets sold and processed by one of the well known and experienced companies. So what if it has a bad reputation, it doesn't stop people from buying up all the tickets. It's probably the easiest decisions as a venue owner. I'm not saying I agree with it, but if you think about it, Ticketmaster is a great resource for owners.
Sounds like someone that hasn't seen music live, physically, for a long time.
Computer speakers are incapable of replicating the sounds and air distortions that your body can actually feel. Computer screens are incapable of emulating the pyrotechnics that your body can actually feel even from way back of the venue.
There are plenty other nuances that limit the utility of a streaming service.
They strongarm venues into exclusivity agreements: all phone and online tickets at those venue must be sold through Ticketmaster.
Even walking up to buy a ticket at some box offices results in a venue using Ticketmaster as point of sale.
Their parent company Live Nation also outright owns many venues, a true monopoly in my opinion.