I'm not sure what point you're making about Ticketmaster. That business is completely different from the rental market (for example, there are probably literally a million times as many providers).
And unlike other up-front costs (first/last/security) it doesn't actually provide value to a tenant in any way. It's a third party that is really only acting on behalf of a landlord, never mind the part where we're talking about literal rent-seeking.
Essentially, it's deceptive advertising, that makes for a less fair and accessible marketplace to consumers. Especially in any remotely competitive rental market (which is a lot of them now, given the way prices have skyrocketed in recent years relative to pay), it's easy to get stuck paying an exorbitant fee simply for lack of a clear way to find out which places don't expect you to pay the third party they contracted.
And that's not a free market either.