I know normally batteries have 5-6 or 7 years (as you mentioned) warranty, but the original battery has only 36 months warranty and the original batteries on my Civic and Pilot lasted less than 4 years for sure, a few months after warranty expired. Damn, they are good.
One day my colleague mentioned this about 3-4 Honda vehicles he owned, then I realized why I had such problem as well.
If you have difference with Honda's original battery, the one comes with the new car, please let us know.