True, but the costs aren't dramatically better for the cheapest EVs, which are still far more expensive than comparable ICEVs precisely because of the battery cost. If it costs a car company £10,000 per car for the batteries (which would get about 35KWh, enough for a range of about 140 miles in good conditions and normal driving), that £10,000 is going on the selling price of the car. It has to - they can hardly sell at a loss.
EVs are currently viable in some circumstances and will probably become more viable in more circumstances in the future. I wouldn't be surprised if they became the norm in just a few decades. If there are dramatic advances in battery technology, EVs would become clearly superior to ICEVs. The potential is there.
I'm just objecting to the false claims about current running costs. 1.5p/mile for a sporty saloon is not a true figure, not by a long chalk, and the comparisons with ICEV running costs are simply fiction.