According to Oracle (TFA), "There will always be a high-performance gratis JVM."
Well, perhaps Oracle are just going to add enterprise-class features to Java - for example, the JRockit hot swapability mentioned in the article. Once you need such features, chances are you are able and willing to pay for these. The rest of the community could continue using Java for non-mission critical purposes.
In time we'll see if this strategy is successful, or not. If demand for features like the ones Oracle is planning to develop is great enough surely open alternatives for some of these will pop up in foreseeable future.
When/if this happens we'll hit the major issue worth discussing: how the Oracle-led and OpenJDK evolution paths will stay at least close to each other. If they diverge substantially, at least one would be doomed... if not both.