Yeah, I mean it's not like supply and demand is an established economic principal or anything.
What you've found is one exampe of supply driven pricing, which tends to be a long term effect. You seem to be thinking long term, whilst I'm talking mid-term - largley because we're not even close to 80% of road users driving EV's and it'll be a while before we are.
Think of it in terms of diesel, which used to be cheaper than petrol, demand for diesel went up and the price followed at a larger rate than the less in-demand petrol which is now cheaper than diesel.