Google helps itself to images, scraping sites to its hearts content, assuming that:
1) If you really care, you will play their game, tweaking your robots.txt and metatags to "opt-out" of their unauthorized content theft/republishing. In many cases, they "damage" the presentation of your content, by showing it in crappy resolution, casting a bad light on the quality of what your site provides. They also effectively hijack your traffic, by obfuscating any link to your site that owns the content.
2) You will find all of "their" copied versions of your intellectual properties (they're clever enough to not hotlink), and DMCA them, with no recourse to recoup lost revenues/opportunities.
DMCA seems to have benefited the largest publishers with "free" access to others' content, while having the resources to "oops, sorry" when called out.
DMCA seems to have taken out the right to seek damages for unauthorized use of content, prior to DMCA notification.
