In hundreds of flights neither me or my wifes carry on bags have been measured in any way!
There will always be some who need to carry things like expensive camera gear on but maybe there should be some sort of acreditation for those.
I can only comment on the system as it affects me and the general increase in the size and weight of carry on bags over the years has got out of hand.
There just isn't room in the cheap seats for every one to take on even their allowance.
I agree that passengers who pay for the better seats should have a bit more lee way, thats one reason way we have different classes.
I can see I am banging my head against a brick wall here, so happy St.Georges day and fly safe.