Solar can be cheaper for daytime generation before it's cheaper for nighttime generation (when you need to tack on the cost of storage). Electric cars may already have a lower TCO, but if you already have an ICE car, it may not be worth the transaction costs of immediately selling it and buying an electric car instead of waiting until you would have bought a new car anyway, whereas it could be if gas prices were higher. The TCO is also affected by how much you drive, so the gas price that justifies replacing your car depends on how much you drive it.

There isn't a price level where $0.01 below it no one can justify buying an electric car and $0.01 above it everyone can. The higher oil prices get, the more people end up on the other side of the line.