There's value in controlling mindshare; keep everything proprietary too long, and people just use open-source clones that may be inferior but can actually be used by the majority of the talent pool.
I believe I was already using EMR when Google's MapReduce service was announced. I'm not referring to their internal tool, but the external service.
...which is sorta my point. People remember the version of the technology that makes it accessible to them, not the first one that comes out. When Google keeps thing proprietary forever and only releases academic papers, people quickly forget just how far ahead they were.
Kind of reminds me of the genius move by Tesla to crowdsource collection of self-driving car information. Experts want to get where they have the data to train their models, and if Tesla propels itself ahead of the pack for number of miles of real-world training data, then that makes them very attractive to talent.