Priced it too high. Priced themselves out of the market. Anyone who has a phone right now that is "good enough" will be sitting out this round of upgrades. 5G will get people to upgrade.
I have a 2010 model I’ve been using daily for web/email since 2010. Never had a problem with it and I’ve ran every beta version of OSX on it. I did make it have 8 gigs of ram at some point and a solid state drive would be ideal in it.