Cars need tremendously high drain for brief periods to start the engine, especially under adverse conditions like winter when oil starts out being cold and less viscous. They also generally don't deep drain the battery. The ability to be optimized for those constraints plus their simplicity and low cost is why they still own that market. This is not my field, but I'm not aware of any battery chemistry that could conceivably compete with them, and because of their lead we'd like an alternative if there was one.