There are long term support releases. I suspect that most enterprise places will end up using only LTS versions.
The real killer with the six month releases is not that they're every six months. That's doable. The killer is that they have zero support (even for security issues, I believe) once the next release comes out. As a result, you have to be ready to switch immediately. If you could upgrade to Java 10, then wait twelve months and go to 12, it would be less painful.
Yeah, the lack of overlap in support between LTS releases is the real killer. I predict that in 5 years there will be few people using the Oracle JVM. People will migrate to the JVM supported on their OS (for example, RedHat supports OpenJDK for the life of the OS as part of their OS/middleware offerings).
The real killer with the six month releases is not that they're every six months. That's doable. The killer is that they have zero support (even for security issues, I believe) once the next release comes out. As a result, you have to be ready to switch immediately. If you could upgrade to Java 10, then wait twelve months and go to 12, it would be less painful.