I am not sure these publications were intended to generate sales of these technologies. My assumption is that they mostly help the company in terms of recruitment. This lets potential employees see cool stuff Google is doing, and see them as an industry leader.

Spanner is literally a Google cloud product you can buy ignoring that it underpins a good amount of Google tech internally. The same is true of other stuff. Dismissing it as a recruitment tool indicates you haven’t worked at Google or really know much about their product lines.

He didn't say that Spanner is only a recruitment tool but that the blog posts about Spanner (and other core technologies of Google) might be.

More people see the blog posts as it’s a more gentle introduction than the paper itself. Sure it might generate interest in Google but it also generates interest for people to further look into the research. They are not for sales of the tech but I’m not sure the impact is just a recruitment tool even if that’s how Google justified the work to itself.

Spanner research paper was in 2012. Bigtable was in 2006. GFS 2003. The last decade has been a 'lost decade' of google. Not much innovation to be honest.

Attention is all you need is 2017... https://arxiv.org/abs/1706.03762

They thought it was dead end, that is why they released it :P