How does the Tor network counter abuse? Like, say you're hosting a service on the Tor network, what does the Tor network offer if anything to defend against e.g. DDoS attacks?

It's a solution for users because you can't afford to demand ID from your users (such as an IP address) if all your users quit when you do that.

Sure, but if the service keeps getting overwhelmed (financially or traffic-wise) or compromised (not even necessarily in the security sense but in the semantic purpose sense, like via spam floods on a message board) due to a lessened capability to combat abuse, then the user is worse off all over again, no?

All it would solve then is laundering Tor traffic from being probably malicious to being reputationally ambiguous. Though for a within-network service, that's probably assumed anyways - hard to run a Tor service if you assume all Tor users are malicious, that would be nonsensical.