We're not frying batteries quicker, we're using our phones longer. The only reason I'd have to replace my 3.5 year old phone is that the battery is dying, but it probably doesn't make sense to spend half the price of my phone (phone was only $200-ish) on a replacement. I just don't have any qualms with my phone or have any particular reason to need a new one. I resent having to replace my phone because a part that could be easily user swapable at a reasonable price point isn't.
Your assumption that phones would only be used for 2 years is pretty weird on an article about using phones for 8 years.