That's a fair point about requiring a larger battery for...

That's a fair point about requiring a larger battery for start-stop, however there is a significant amount of cars and after-market options going towards Lithium for that purpose, including replacing the normal 12v battery in your car.

Hybrids however have a slightly larger battery and already use Lithium.

I think wherever there is a transport product (vehicle battery), Lead doesn't have much of a future, especially with the falling Lithium battery prices.

Stationary storage however, where size and weight don't matter so much, Lead may get more of a foothold, though most of the deployed grid-scale and household batteries today are already Lithium.

My point, don't count on Lead for vehicle batteries for much longer, even the simple starter-motor battery in older traditional cars is going Lithium, evidenced by the 12V Lithium options already in stores in Australia. Costs are high today for Lithium options, but they are falling.