So schreibt es Oracle unter https://blogs.oracle.com/java-platform-group/the-future-of-javafx-and-other-java-client-roadmap-updates
Starting with JDK 11, Oracle is making JavaFX easier to adopt by making the technology available as a separate download, decoupled from the JDK. These changes clear the way for new contributors to engage in the open source OpenJFX community. Meanwhile, Oracle customers can benefit from continued commercial support for JavaFX in the Oracle JDK 8 through at least 2022.
With the Java Platform Module System in place since Java SE 9, it now more viable to decouple JavaFX from the JDK, in order to make it available as a separate download. This will make it easier for developers using JavaFX to have more freedom and flexibility with the framework. Moreover, with our focus on increasing the release cadence of OpenJDK, JavaFX needs to be able to move forward at a pace driven by the contributions from Oracle and others in the OpenJFX community. Oracle plans to implement this decoupling starting with Java 11 (18.9 LTS).