Hi there! Author here. What I was referring to was MapReduce/BigTable. While I think BigQuery always had SQL support, some customers in the early 2010s had the perception that Google was more interested in building a new language for queries rather than support something for SQL.
Mike Stonebraker talked a little bit about this in the context of MapReduce on the dbt podcast recently: https://roundup.getdbt.com/p/ep38-a-romp-through-database-hi...