His prediction was based on projecting technology curves out and comparing to a set of requirements around acceleration (able to merge onto a highway), range, and cost. Such projections out decades in advance are naturally imprecise. I would have considered it a darned good prediction if the first mass market electric cars had arrived anywhere between 2015 and 2025.

The majority of new vehicles being fully electric will happen pretty soon. The economics of this happening are incredibly compelling, essentially inevitable. I would put this occurring before 2025, but it's hard to say. If the Chinese keep up the heavy push toward electrification, it will probably be sooner. If not, then later.