Yes and no. Observation in the workplace does tell me (and others) that there is a real qualitative difference in the way most people work and the quantity of the output they produce depending on their age group. It is by no means everyone, and I'm sure that people who were in the workforce before me felt the same way about my age group.

It really stood out to me when the son who is now 30 remarked about how lazy and non-productive the 28 year old is.

I don't know that "millenials" is the right term though. I noticed the decreased productivity in new members of the workforce around 2000. It is coming up on twenty years later