Look how long it took them to go from vented batteries which used to spew acid all through the engine bay to sealed gel type and yet the sealed gel type had been available in the maritime sector for years. A high discharge lithium battery is pretty easy to make but would cost a lot more than a lead acid battery and every penny counts when you are called Ford or GM.
Hi , Are you not being unfair to the motor manufacturers .
Motor manufacturers are pragmatic and unless there is a good reason for change, why would they. Startarting car is an ancillary activity to the purpose of driving it and once one has a satisfactory method of doing so why change?
The SLA batteries will last 6 to 7 years, longer than most original purchasers will keep their cars. The SLA has a number of advantages in cars , it is not excessively heavy, not much more than a sack of potatoes or of groceries, has superb cranking power. 300 A +. and pretty well suited for the role. There is a huge manufacturing and distribution network available. What SLA s are not good at are deep discharges, but that is not a problem in motor starting.
SLA s also do not need additional electronics to keep them safe. They are robust.
A Li ion battery will not have the same safety record remember the Boeing aircraft being grounded..... And does not have the same cranking ability. Yes there is a small market for high power high current batteries at exorbitant prices. Why would you assume that like ion cells are easy to make? If they were would they not also be priced at similar price to SLA types.