Oil briefly went negative a few years ago. If you decided to build a storage business dependent on negative oil prices for profit, you might just be coming online around now, and very much poorer than you were before. (Of course you would in fact have stopped a long time ago.)
Solar panel production on the other hand is exponential and growing much faster than overall power consumption. It can be very, very favorable to build batteries and that's why grid scale battery production is taking off. There is in fact a storage business dependent on energy arbitrage over time, it's lucrative, and all indications suggest it will continue to be lucrative for many years to come.