What I've read and seems to be backed up by how fast utility batteries are being installed is the drop in price of batteries means that suddenly the payback period for batteries is a couple of years.
Batteries exist in a different economic regime than rate payers. Where the price per megawatt varies by 2X or more. Which makes it easier for batteries to make money be arbitrage. As in buy power at 10am for $40/MWH, sell it at 7pm the same day for $80/MWH.