That's actually what they did before the Tesla, and the result was the cars were so useless nobody wanted to buy them.
Most carmakers make small subcompact EVs, and they are way more useful now, but even Dacia Spring which is probably the cheapest European made EV, isn't competitive against similar sized or prized ICE cars. And frankly it's a very unattractive car in many ways IMO.
ICE cars have a century of iterations and optimizations on cost effective production and efficiency, it will take a while longer to get the EVs to the same level.
Batteries are getting both cheaper and better and safer, so there is no doubt EVs will ultimately surpass ICE in probably every segment.