[jungturk]

Aren't lifetimes closer to 10+ years due to better battery management (managed operating temperature and charge/discharge)?

Tesla suggest such with its megapack https://en.wikipedia.org/wiki/Tesla_Megapack

[sudosysgen]

Only if you don't do daily ~80% discharges.

You can avoid that right now because the grid has baseload. But if it doesn't you can avoid the wear cycles.

10 years is about what you'd expect if you only discharge ~30% of capacity daily, which is how it is operating right now.