The problem is that batteries are expensive. High-end cars have high margins (it doesn't cost 2x as much to build a $50k car as it does to build a $25k car). When Toyota introduced the Prius, they added all sorts of (what were then) $30k car features. Why? Not because they wanted to make a luxury car, (a friend of mine remarked that if they just added leather seats he would buy one instead of an expensive Lexus) but because it costs next to nothing to add those convenience features. That way people compare the Prius to a $30k car and see only a $1000 hybrid premium instead of a $5000 premium. That's also why you don't see $15k hybrids: Taking all the "premium" features out don't make it cost any less.

The reason this is possible is that hybrids and EVs have the margins of much less expensive cars.

Edit: added a sentence