It’s partly this but also the artists benefit in other ways from large strata of their fan base being able to attend live shows, but merch in person and mingle with each other. The venue and Ticketmaster only benefit from the ticket sales.
Scalpers are also a source of guaranteed sales, so you're diluting the risk of a concert because someone is already buying up all seats already for you and running the risk of not being able to sell them at a higher price later.
