Clearly EVs aren't there yet for the very bottom of the market. This market will buy used for another decade and then all the sudden will start buying cheap used EVs. Used EV prices are dropping and will continue to drop, but it takes time. In the meantime, wealthy people that were already planning on spending a lot of money on cars will increasingly buy expensive electric cars and prices will come down. Pretty much every manufacturer is targeting a $10k drop in price for the next generation.
And to answer your question about where are the affordable EVs - China.
You're right that cold winters in northern latitudes present additional system constraints. But that doesn't mean the renewables + storage strategy is flawed, it means we need more transmission and more storage, and gas backup will linger longer in such areas than it does in warmer areas. We're still early in the transition and have a ton of low hanging fruit to capture before we need to really focus on the remaining 20%.