In summary the idea was to start with expensive electric cars (roadster, model S, model X which was initially not planned) to fund research on affordable electric cars (model 3 supposed to be first of them). As electric cars are becoming more popular and there are technological advances, we'll get them cheaper and cheaper.
This was written 10 years ago:
https://www.tesla.com/blog/secret-tesla-motors-master-plan-j...
In summary the idea was to start with expensive electric cars (roadster, model S, model X which was initially not planned) to fund research on affordable electric cars (model 3 supposed to be first of them). As electric cars are becoming more popular and there are technological advances, we'll get them cheaper and cheaper.