I think the main point of the 'million mile' battery is that it...

I think the main point of the 'million mile' battery is that it means only ever one battery per car. Nobody will ever need to consider the need to eventually replace the battery and that should remove perhaps the biggest obstacle to buying and EV.

Initially this should means a faster uptake of sales and hence more stress on the supply of lithium for several years. The longer term potential decrease in lithium demand will be quite a few years down the track (and perhaps removed althogether because of the use of batteries in storage - lithium would certainly become more competitive with vanadium in long term storage).