I don't think that punishment is necessarily effective in the long run either. If you are good at dirty SEO, you will accept your punishment on one site/business and restart with a different site/business, and hopefully last longer until getting caught this time.
With the goal of minimizing overall dirty SEO, Google shouldn't get caught up in an over-emphasis on punishment. Especially when the website being punished is actually the website that should be chosen, and they only use SEO to compete with other SEO.
> If you are good at dirty SEO, you will accept your punishment on one site/business and restart with a different site/business
It's not a black/white issue, sure for a very spammy website, it would work less (because that website is still out of the picture). But for a grey website like rapgenius, it would surely suck a lot more, because they would lose all their brand image, etc, which is quite something to build.
With the goal of minimizing overall dirty SEO, Google shouldn't get caught up in an over-emphasis on punishment. Especially when the website being punished is actually the website that should be chosen, and they only use SEO to compete with other SEO.