https://en.m.wikipedia.org/wiki/Abundance_of_elements_in_Ear...
The cost difference (which is only 4x vs aluminum, apparently) is due to a combination of increased demand (not enough production capacity) and probably the amount of energy/environmental impact of the two processes (you have to go through a lot less ore/brine to get the aluminum).
Also, aluminum benefits from a robust recycling infrastructure that hasn’t come online for lithium yet.
Recycling lithium in the form of extracting from batteries produces a significant amount of chemical waste, meaning that the cost savings of recycling is significantly less when compared with the difference between smelting and recycling aluminum.
Even so, despite the enrichment it remains about 500 times less abundant than aluminum (in atom numbers, which matter for batteries; in weight the lighter lithium would appear even less abundant).
Moreover, the lower concentration of lithium in typical lithium ores means that for mining equal amounts of lithium and aluminum the environmental effects of mining lithium would be much worse, because more rocks are disturbed and more waste is produced.
So there is no doubt that replacing lithium with aluminum for large-scale energy storage is a more sustainable option.
Your graphs show it. They also show that there has not been a substantial reduction in its price over the years.
This means there is market potential for other (al/sodium) chemistries, mainly for grid-level storage.
Electric cars (by far the biggest consumer of lithium) have been experiencing a an average compounded growth of something like 50% per year for the past 10 years. Li production is still catching up. The earth has plenty of Li deposits but there is a lead time to purchase the heavy machines needed to turn those deposits into productive mines.
Once electric car growth hits the inflection point on the adoption curve, and growth becomes sub-exponential, we'll start to see major downward pressure on Li prices.