I certainly agree older folk yelling at younger whippersnappers is a constant, but turn it on it's head for a moment: when it happens the other way around, no one questions it. "It's the Boomer's fault!" Millennial's proclaim, and every culture mag now runs a similar story.
There is something to be said for the wisdom of elders. Yes we should discard the grumpy old complaining because of change, but are we to really say all the complaints are invalid just because "it's always been done?"
I think of other societies, primarily Asian, that have deep respect for the thoughts and opinions of their elders. I think of how almost every faith, including the three major abrahamic religions explicity command followers to honor thy mother and thy father (which is generalized to honor your elders). Yet in this country, and most western countries, the fad is to kick the old out as soon as you can! "Out with the old, in with the new! Pay no mind to old people's grumbling! Their wisdom is invalided! Their opinions on culture and where society is headed is invalid!" -- And one can only wonder, is this why history is doomed to repeat itself over and over again?
We blow off what the "geezers" are telling us "Psh! Get with the times old man, things are different now!"
In my opinion, humanity hasn't changed much in the past couple thousand years. We would do better to listen to some more grumblings of the geezers. Maybe getting off a lawn or two wouldn't be so bad after all.