The industry perspective is that nobody cares (and rightly so).

I was at the conference where this was presented. The paper is terrifically written, and it's good that someone is investigating this.

That being said, it's just not that big of a deal. In practice, this will never be a problem for anyone writing Java.

The Java wildcard system is insane and no-one is trying to build type systems based on these ideas, not even Scala and the new batch of JVM languages (Kotlin, Ceylon). They have their own problems, but this isn't it.