I don't think it's a pure technology issue, as in the big boys don't know how to do it or develop some amazing rocket science... Perspective: I saw in the article 111,000 Model 3's sold YTD, and from another source round numbers 17.2M total new cars sold in the US through November making Tesla's market share with all models included sub 1%.
Musk has been successful with marketing and creating a new segment in the market for EVs. I see a Tesla, I know it's different and always electric, and boy is it expensive and unique. Worth the price for recognition and status for those buyers. I see an Audi, Mercedes, Jag, etc. it's probably a gas engine, and I've seen em for years, nothing new. Oh, you say it's electric? Meh. Gas is $2.25 a gallon around the country. (forgive us OP in Cali)
For me it boils down to Tesla being more of a unique status/recognition sale. Don't put an electric drivetrain in my otherwise daily driver SUV that looks like the rest of your already known gasoline lineup until gas prices hit $5/gal, then the EV segment may be large enough for 10 players with 3-5 models each.