I really like Theory X and Y. The reality today is probably in the middle, there is a mixture of these. This is micromaniging (that I don't like at all) vs hands off (but you need trust). Both can (or can't) be applied in different situation. For example I will not use Theory x (and micromaniging) for a team of experts. If a team is not motivated, Theory Y is not the right solution.

I would like to share an interesting study run by Nielsen on the generational views (not only Millennials and Baby Boomers but even Generation Z, X and Silent) about how we live.
http://www.nielsen.com/uk/en/insights/news/2015/the-facts-of-life-generational-views-about-how-we-live.html

I would say a big difference is in the speed, size and number of simultaneous 'cycles' in which they work. What I mean with that is that 'older' workers tend to prefer spending larger amounts of time on single tasks for a longer time to bring these to a close. 'younger' workers tend to prefer spending shorter amounts of time on a single task, work on more tasks, and also more of them at the same time. That makes combining older and younger people in a team a challenge (how to align the cycles), but at the same time an advantage: you have two different preferences that help you cherrypick the best each time.

Note that the way younger people work is very consistent with the way the use e.g. social media: short focussed attention burst. And also how ways of working that get more and more into vogue operate. Think of Agile Scrum or Design Thinking: short fast cycles - it's OK to fail (that's how you learn!) and move on. Don't think and specify everything out in detail before you start ('old' way of working)

If by "lifestyle performance management," you mean what we've previously called "work-life balance," I would say that Millennials have generally figured out there is no such thing as "work-life balance," only work-life management. As a boomer who has supervised multi-generational teams, I have learned from the Millennials in particular that quality of life depends on making time for life elements other than work! It doesn't come naturally to Boomers or even Gen-Xers, who are more socialized to keep our heads down and work, rather than mixing in breaks, family time, and investment in activities that regenerate our energy and enthusiasm for our jobs.

'Theory X' and 'Theory Y'

'Theory X' and 'Theory Y' are theories of human motivation and management. They were created and developed by Douglas McGregor at the MIT Sloan School of Management in the 1960s.

These theories describe two contrasting models of workforce motivation applied by managers in human resource management, organizational behavior, organizational communication and organizational development.

Any thoughts?

This article might throw some light to the question asked here

As is always true, older workers can teach younger colleagues a thing or two. But education is a two-way street, and older workers can also learn from newer hires. 

https://www.monster.com/career-advice/article/generational-teachback