It was just a coincidence. They do it right: ship when it is ready. LTS is not an openjdk term it is something that vendors might offer for any jdk version.
LTS was proposed by Mark Reinhold [1] who leads the JDK Project in the OpenJDK community in 2017. There was a lot of discussion [2] that resulted in many vendors supporting and adopting the LTS model.
It's a thriving ecosystem (which is great!) but yes, Oracle does contribute a significant portion [3].