When you use an energy source with a 90% capacity factor instead of 40%, you can amortize the CAPEX twice as fast, and there's a lot of CAPEX involved in the business of making green hydrogen (that's most of the cost, actually since it assumes very little OPEX due to using excess (hence free) electricity).
You ignore the cost of overbuilding nuclear vs the cost of renewables. I doubt that you can make a convincing argument that fits in the HN comment box, since it's a rather complex topic.
