They can actually end up in jail if you provide sufficient evidence that proves who was responsible for the DDoS attack.
Check this out: (this is for the UK but I'm pretty sure there is something similar for the US too)
And in my opinion the only way DDoS attacks in video games will ever stop (atleast the ones been made from rookie hackers that mostly appear in video games) is for people start going in jail, but people just don't care enough to report them to the authorities.
There are ofc some real hackers that are clever enough to not get caught, but the everyday rookie video game hacker who uses google to learn about this kind of attacks can easily get caught. I'm pretty sure they don't even google what the consequences of such actions can be.
So, in my opinion if you really want to punish this kind of people you should start reporting the DDoS attacks to the police, they can actually end up in jail. I know that requires spending a lot of your time due to a retard, but if the attacks bother your parents work, I think you really should take that time man. You will also be making good to the videogame community.