There is no grand experiment here, what differance does 5 years make?
The answer is the younger pilots might have to wait 5 years longer to get a command or transfer on to a larger aircraft type-nothing more.
The 60 year old age barrier has been in place for 4 decades+. 60 used to be a much older age in the 1960's than it is today. We have to move on and cannot live in past for ever.
For those of you who do not like the overdue change, your day will come and you will no doubt be glad then that you will have the opportunity to fly for 5 years more.
The retirement age should have been changed years ago. Look how wonderful the 57 year old pilot who ditched in the Hudson was. What further proof does one need that years of experience is an advantage and not a disadvantage?
65 is not so old nowadays, you will all be there one day.