Scalping has existed since forever.
The thing was it was local promoters + local sales (aka criminals) who would get tickets from management (yes thats the artists management) and kick the money back to the artist if they were lucky (if not the management kept it).
Now TM owns the venue, they are the promotor, they are the manager(to an extent) and have full control of the tickets, and the secondary market. The artist is now 100 percent in on the action making fans buy a fan club membership then get "face value" tickets at presale only with expensive meet and greet packages that range from a few hundred bucks to a 1000. An artist can tack on 50k to several 100k doing this at every date/venue.
As for TM's uncharges, most of that is because the artist either demands they do it (my prices are reasonable) making TM the scape goat, or they want a sum that is the total of the door and TM needs to cover venue costs and make profit so that just gets baked in as a "fee".
Just to put a fine point on this. In the old model promoters, venues all of those entities being separate and charging a markup made sense. When TM consolidated they didnt change the markup they just kept the margin...