Probably. If nightly base-load power becomes as demanded as daily base-load, then the price would equalize and neither day nor night would be cheaper. However, some level of incentive would still need to be kept, otherwise the spike of car charging would just be shifted to 1800-2000, when everyone gets home and plugs in.

And really, the aluminum smelters was just one example. As the nightly price equalized with the daily price, all electricity would begin getting more expensive, and everything else with it. Much as, in current times, increases in oil price can increase the price of everything.