As an early participant, while someone might have had this plan, I certainly did not hear this ever stated by anyone. Having the ability to run on Mesos was discussed as interesting and in the spirit of community but the work we did treated Mesos as a source of learning but not as a serious thing to integrate. I’m sure others considered it, but as justicezyx says it was an inclusive idea but at best something a few people cared about.
I meant to say that that I never heard any significant decision maker had that plan on K8s' future.