They still have to solve the charging problem. Waiting at a station is a huge inconvenience, and a lot of people (myself included) can't charge at home.
LifePo4 was big for that exact reason, with much much faster discharge rates, as well as lower weight per capacity- the catch was the steel plates needed for fire safety added more weight back
iirc it's something like 0.3c at best for SLA type batteries and a flat 1.0c for lifepo4 (so lifepo4 can charge/discharge at 3x the rate with the same capacity)
if they can ditch the steel plates, they could fit a lot more battery in the same sized area, hopefully keeping the faster rates and smaller size overall
Lithiums biggest weakness is the cells are stuck at roughly 3.6v (early lithium batteries) to 3.7v per cell (Current lithiums) with a boost of 4.2v peak, fully charged. They can't do that for long term without damage, but need it sometimes to balance multiple cells - it's why they got chosen for phones since USB at 5v can easily charge one those cells with voltage to spare, even if they droop under load
This is why 9v and 12v quick charge methods exist because you can slap 2x or 3x lithium cells in parallel for more ah at the same voltage, and then seperate your 9v charger into 2x 4.5v and charge two cells seperately (same with 12v into 3x 4.0v) - this is also why the quick charge methods drop off as the battery % rises
Equalising cells to keep the load even between them all is how you keep them alive without one being overcharged and becoming a spicy pillow, and this trick helped them achieve that more easily - it gave you faster charging, and let them seperate the charging between the cells (if they used multiple)
You can't easily make them bigger or smaller, you can only add more cells of a fairly standard size - which becomes awkward when your voltages have to be a multiple of 3.6v,forcing buck converters to be needed for a lot of designs - or devices to just be designed around their optimum voltages (phones!)
Phones make it easy with being made for those voltages, because they can keep things in the happy range and avoid the highest charging rates, and power off long before they approach the 'danger' levels - a phones 0% reading may well be 30% of the battery, not the 20% they degrade at
This is why we dont see AA/AAA lithium batteries, since they have to run at 3.6-3.7v and fit a buck converter to drop to the expected 1.5v which takes up space, lowering the capacity