marketing matters. electric cars have been around for 100 years, but they weren't getting any measurable adoption until Tesla came around and made them seem cool. I don't like a lot about Tesla or Musk, I'm not sure they have what it takes to mature, but you can't dismiss the effect their shenanigans have had on the industry.
Conventional car companies have worked on electric cars, and have their own models for decades.
Tesla's unique proposition was about building an electric supercar (and even that is not working very well, profits wise).
They'll hardly be the one's replacing the mass oil and diesel cars with electric models...