The dutch auction doesn't solve the race aspect. There are plenty of situations where people can't buy tickets when they want - they're at work when the price is reached, driving, the webserver is at capacity, etc. Scalpers have the advantage in all these scenarios.
Secondly, people will pay more money once scarcity and FOMO kick in. I may want a ticket for $40 but scalpers knew X would happen somewhere around $50 so they bought all the tickets then. Am I not going to see the concert for $75 buying a scalper ticket? Not a straightforward decision to make! These are the sorts of inputs scalpers will consider when deciding X.
Secondly, people will pay more money once scarcity and FOMO kick in. I may want a ticket for $40 but scalpers knew X would happen somewhere around $50 so they bought all the tickets then. Am I not going to see the concert for $75 buying a scalper ticket? Not a straightforward decision to make! These are the sorts of inputs scalpers will consider when deciding X.