Legal solutions aren't going to kill all spamming until we acquire Un-bribe-able World-Wide Pork-Product-Hating Overlords. But a large amount of spam actually does come from US-based spammers, including little guys and big businesses. It's extremely easy to comply with CAN-SPAM if you're not a deliberate spammer - don't send people unsolicited commercial email and you've done your job. It's pretty trivial to comply with it even if you *are* a deliberate spammer, and cheap and easy to set up a $100 shell corporation to limit your financial exposure even if you're a deliberate spammer who doesn't want to comply with the trivial rules. If Dan is making money suing you, then you're a) spamming, b) lazy, and probably c) stupid. If your primary problem is c) stupid, then you deserve to be slapped on the wrist with a couple thousand dollars worth of lawsuit and told to stop annoying people. If you're not stupid, just greedy, then you deserve worse, so I'd recommend spamming him lots of times.
Not only do legitimate companies and groups not send people unsolicited email, they maintain mailing list systems that let people unsubscribe, so even if they have spammed you, it's easy to unsubscribe once from all of your future email. Of course, most people have learned not to trust unsubscribe-from-spam systems, because that just gives spammers more data, but if you really are legitimate (e.g. you're a newspaper, somebody registers for your online comments system, and then decides you're sending them too much mail) you'll do that. And if you're legitimate and not stupid, you're certainly not going to buy mailing lists of "opt-in addresses" from untrustworthy sources.
The purpose of the laws that let individual spam victims sue spammers isn't just to let us get recompense for the 5 seconds of time it takes to read through a message that slipped though our spam filters - it's to let large numbers of people take care of the job of prosecuting spammers, since the criminal prosecution system isn't going to bother with the small-timers. The reason for allowing it to be done in small-claims court is to make it much easier for us to to that. And yeah, it does encourage the spamming business to professionalize and let Russian mobsters do the jobs that used to be done by real American workers living in their single-wides chasing "make money fast by spamming" scams, but getting rid of home-grown stupid spammers is an important part of cleaning up the Internet. But it also encourages the anti-spammers to professionalize, and good for them!