I couldn't make it to SF, but it's all available online --
https://cloudplatformonline.com/NEXT2016-Live.html - and I was already able to catch most of it, including Eric's own keynote.
I do recommend watching the livestream, but, TL;DR, WITH a bit of context that obviously Twitter tends to be pretty poor at...: offering JUST what we thought developers should ideally be using (App Engine, with just Python, only Datastore / no SQL, etc) just didn't work in terms of getting us market share -- by more or less sticking to just that one line for years, we missed a much vaster slate of developers who just couldn't consider a complete, from-scratch rearchitecting. So we kept expanding it, both within App Engine (more languages, the flex environment nee MVM, easy SQL access via Cloud SQL) and outside it (IAAS such as GCE, SAAS such as BigQuery).
Absolutely no reason to have this cause any anxiety about GAE's future. So much new GAE stuff being announced at this Next conference should, on the contrary, eliminate any anxiety one might previously have harbored.
Alex