In 2010, smartphones were just taking off, every new generation offered significant improvement. 2010 smartphones are terrible by today's standards: small stora

In 2010, smartphones were just taking off, every new generation offered significant improvement. 2010 smartphones are terrible by today's standards: small storage, underpowered, no 4G, bad camera, etc... 2015 smartphones are a different story. Things have stabilized, and a good 2015 smartphone should be perfectly usable today, a bit sluggish, but usable. And interestingly, that's when they stopped having user replaceable batteries. More generally, the market shifted from real obsolescence to planned obsolescence.