Anecdotally, iOS 11 made my iPhone 6 run slower than iOS 10, but iOS 12 made it run faster than iOS 10. (This is in line with other reports and benchmarks you'll find if you go looking.) There's an awful lot of snark about iOS slowing down with each successive version, but I'm not at all convinced it's universally true. (Again, anecdotally, I'd say iOS 7 and 9–11 were guilty of that.)
At any rate, the big issue I tend to hear about Android phones getting updates is "my Android phone isn't getting updates." My iPhone 6 shipped in 2014, and iOS 12 actually ran on 2013's iPhone 5s. How many Android phones that shipped before 2016 are getting Android P? Are there Android phones that shipped in 2016 that aren't?
At any rate, the big issue I tend to hear about Android phones getting updates is "my Android phone isn't getting updates." My iPhone 6 shipped in 2014, and iOS 12 actually ran on 2013's iPhone 5s. How many Android phones that shipped before 2016 are getting Android P? Are there Android phones that shipped in 2016 that aren't?