Imho, if Google adopted a "cheat once, get banned" policy, most SEOs would drop most of their techniques. As it is now, they'll do whatever it takes and if they catch a penalty, remove the most aggressive things and ask for reinclusion. Voila, instantly back where they were before the penalty. If there was a risk to burn the domain for good, that looks very different.

On the other hand, the opinion of many marketers is that the SEO battle is lost, and if you want good placement on Google, you buy some Ads.