How would we ever get there?

The cost to build and maintain powerplants is expensive - whether it's solar, wind, hydro, or nuclear. This cost needs to be amortized over the life of the plant. It's hard to imagine this getting to less than $0.05 / kWh.

Construction costs alone make Nuclear Energy cost ~$0.08 / kWh even in China where construction is relatively cheap. Even if we get Fusion energy, AFAIK it's unlikely the construction will be substantially cheaper.

Obviously if anything was free - people would abuse it. You would need to build endless powerplants (which cost money) to provide free energy for people to launch rockets and mine asteroids and produce fertilizer and desalinate water...