And the truth is that I only ever said that there isn't enough grid storage available to make renewables feasible for decarbonization. The notion that I ever said there wasn't enough lithium in the earth's crust isn't the truth. Sure, there's more lithium that's inaccessible. But inaccessible lithium isn't available for use in energy storage.
> Last I checked, Li-ion was about US$111/kWh https://dercuano.github.io/notes/energy-storage-efficiency.h... which is probably around US$300/kW on th current grid, depending on how many hours a day you need battery, and buyers were undervaluing storage. Given that coal and (1970s) nuclear plants cost on the order of US$1000/kW to build, this is already economically feasible. (Current nuclear plants cost close to US$7000/kW, but plausibly that's largely regulatory costs.)
You're comparing figures on generation to storage. Yes, a big nuclear plant that generates 2.5 GW of electricity often costs $15 billion, sometimes more sometimes less (The Taishan plant only costed $7 billion for 2GW). But they generate that power for 50 to 80 years. And crucially they generate power 24/7 and don't need a supplemental form of storage.
By comparison, buying 2 gigawatt hours grants you the ability to store enough energy to output 2 GW for a duration of 1 hour. This means something totally different. You still need to add onto this the cost of building and maintaining solar panels or wind turbines or what have you to actually fill this storage.
But what's crucially omitted here is service lifetime. Good lithium ion batteries will do ~1,500 discharge cycles, exceptional ones 2,000. That's 4-6 years of service life for these batteries, especially if they're being used for diurnal storage like solar. And that's really all they're good for, batteries also lose their charge if they sit unused for long durations. so $100 for 1 KWh that needs to be replaced every 4 years really costs $2,000 over the life of 80 years.
Also actually attempting to use batteries for grid storage will cause the price of batteries to skyrocket. Globally ~300GWh of lithium ion batteries are produced annually [1]. The world uses 60TWh of electricity daily. 1 day of storage would take 200 years to provision at current production rates. Sure, battery production is growing but won't be able to keep up with demand and price will rise. As you pointed out earlier, only 20 minutes of storage are available with existing mining techniques so extraction will rapidly become a bottleneck.