i’m not sure you can blame poor coding by Facebook onto apple.
It was never about blame. It was the observation that as processors become faster, developers take advantage of that performance to make their apps “better”, rendering them slower at best and unusable at worst on older platforms. Facebook were the (very) obvious example.
Personally I like the new phones, but it’s interesting/disappointing that the iPhone 5 has in essence become obsolete in 1 year. When the 4 came out, the form factor did not change until the 5 came out. If you had a 4, it still looked like the latest iPhone even when the 4S came out, so it had a long shelf life. Not a good strategy to encourage upgrades, but it was a big plus point for iPhones.
After 1 year the aesthetic of the iPhone 5 is dead, yet the 4 lives on in the 4S. My wife’s 3 year old 4 now looks more current than my 1 year old 5.