I saw an interview with I think the CATL ceo and he was saying it's quite a headache ensuring the batteries last that long. Grid storage companies want 25 or 30 year guarantees. It sounds like sodium may have the advantage there.
Net Present Value isn't quite the right thing to look at. Inflation-adjusted energy prices have been rising over time, so the thing these batteries are projected to deliver (fixed impact on that electricity grid) increases in value over time even after the NPV discount. The more important component is the "risk-adjusted" NPV, which may or may not make tech like this effectively worthless.