Nobody was saying that age was relevant or that newer is better etc. I agree, Jet2's planes are in great condition considering their age. FR however will always want brand new aircraft so they can call themeselves the greenest airline with the newest and cleanest fleet etc.
In both these respects Ryanair fails
Not so sure what you mean by that. There's nothing wrong with FR planes. Yes they maximise their usage with nothing more than a quick litter check between flights but they are reliable and well looked after. Remember that FR have very big maintainance bases in Prestwick and Stansted so aircraft are regularly maintained.