Is it? That's the thing we literally mass produce in factories. I think it's the machinery to do voltage conversions and transmission that is the critical cost factor.
From a competitive point of view, yes. The conversion hardware is common in both cases, the difference is one side needs more storage than the other. As others have stated, with the propagation of EV voltage conversion equipment, that's essentially mass manufactured too now.
Edit: I'd also like to add that for something cheap and mass manufactured that we shouldn't concern ourselves with, we sure don't have a lot of it on a grid that already delivers some of the most expensive power in the world. ie one that should be able to afford it a lot more than others
