The BIGGEST problem with clean energy

Something you missed.  Tesla.

Tesla has developed a new form factor for batteries which is expected to bring the cost of cells below $50/kWh.  Their tabless, dry rolled 4680 cells are on track to revolutionize batteries.

Their 4680 technology is not wed to a specific chemistry.  "Lithium-ion" chemistries are likely to be used in performance and long range vehicles because they store more energy per volume and weight.  But for most EVs and grid storage the best chemistry of the moment is lithium iron phosphate (LFP).

LFP battery materials are very abundant and cheap.  LFP batteries have very long cycle life.  The LFP cells I'm using with my solar panels are rated for 10,000 full cycles.

$50/kWh / 10,000 cycles = $0.005/kWh.  Half a penny.  
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There may be a few times per year when we need a dispatchable generation source as cycling only a half dozen times a year wouldn't go very far to pay for LFP cells.  That role might be taken up by running existing CCNG plants with methane recovered from urban and agriculture waste streams.