In another HN article comment someone mentioned that it took Google Brain over a year to replicate the DeepMind AlphaZero code even though they are part of the same company. Yeah, I think there are barriers to communication there.
The first time I was at Google (~2010) you could send an e-mail to any engineer in the company and you'd get response offering to collaborate within an hour, and usually a CL under review by day's end. The second time I was at Google (present), it takes multiple quarters to get teams that report up through the same director to agree on who's doing which work.