I'm not sure what the author (or Yegge, for that matter) expect a good timeframe to be for deprecating services. Anecdotally, Google announced the changeover of Cloud logging API versions in October of 2016, with a 5-month ramp (October to March) to switch from the v1 beta API to the v2 beta API. Five months is nearly two quarters, which is quite a long window for a beta API IMHO. That having been said, Google's habi…
As for the beta thing: GCP's definition of beta was basically everyone else's definition of GA, since the GA requirements were so insane (e.g. 99.999% internal availability) that getting there would take literal years (see the GCF beta to GA taking like 18 months?). I totally agree that it's weird that things would stay in beta for so long, as opposed to hitting industry standard levels so users can have confidence in them, but setting GA as far higher than the industry was part of Google Cloud's plan.