I think that would actually be a good field for machine learning: To separate sound-alikes from copycats.

It always bothers me that these claims are often about a simple melody, while arrangements or rhythm patterns seem to be fair game - if I would use the drum patterns of "Smells like teen spirit" in my song I don't think Grohl could claim anything. But if I would go "Coding in my Pyjamas" with the melody of "Living on a Prayer" I'd have Bon Jovi's lawyers in my mailbox in a heartbeat.

But that being said, I think the copyright overall should be a lot more relaxed with a lot more leeway for creatives because the status quo is just ridiculous.