100$/kwh on a battery that does 1000 cycles is 10c/kwh, 5000 cycles ("Claimed" lifepo4 these days), that's 2c per kwh. These aren't that unreasonable, albeit one would need to account for cost of capital and so on increasing these effective numbers.

Batteries are already economical in most grids where they can arbitrage daily prices of 0-10c during the day to 10-30c during the night, with the occasional outlier event contributing dollars per kwh.

They will never load-shift across seasons, agreed, but for daily loadshifting they are already economical, and being 90%+ efficient (and very simple/easy to deploy and scale) is part of why they're popular. It opens up power shifting opportunities that aren't just daytime solar too.

They are doing seasonal storage - i.e. on a timescale of a year! So no, they are not doing 5000 f*king cycles!

This is systematic fraud by the renewables industry and should be called out.

you're undercounting cycles for batteries. batteries are quoted for until 80% capacity is left which makes sense for mobile applications, but for grid storage, a battery that's 80% degraded is still useful. as such, you probably get 15-20k cycles before it's worth recycling