Only a levy can help the German publishers
But why a levy, which is chump change for Google, and not a property-based market for digital news?
Because there is no value for such a market. There are too many websites who are willing to let Google scrape all of their data in exchange of some traffic. The German publishers have clearly demonstrated recently, when they asked Google to show their snippets, even for free. In fact (though it will probably not come to this), the German publishers would probably be willing, on the contrary, to pay Google for showing their snippets. Quite a few websites do this; it is called online advertising, and Google has some experience on the topic.
The problem the publishers have is not that Google scrapes their data; it is that the Internet exists, and contains a lot of cheap competitors who are willing to whore themselves for clicks, and that search engines in general and Google in particular forces them to compete with all this competition. Would Google not exist, the publishers would be in practically the same situation with any number of other search engines, and those might even charge them for the privilege of giving them traffic.
So the levy is the only possibility that remains. It more or less amounts to declare that quality news publishing is not profitable, yet positive for the common good, and so must be subsidized by some kind of tax on businesses that are profitable.