It seems to me like you’re comparing the costs for building one at the most out there location possible. Putting the questions aside if building anything in such locations would ever be profitable enough for something to be build, or if fast-charging is absolutely necessary: This absolutely isn’t true for the majority/average location, where your solution is the one that prohibitively expensive, not to mention that a good chunk of people wouldn’t even need a charging station at all when they can charge at home, maybe even using the solar panels already on their roof.

If anything, I’d say that specialized EVs with swappable batteries (which already exist) that can then be charged slowly with solar will become viable as they’re much cheaper and efficient in those areas.

^Numbers^ ^made^ up^