Good for them - I cant say as though I would be happy to retire at 27 - it depends on whether you get satisfaction from your work.
I am not against property investment - notwithstanding your example above, I am firmly of the view it is much more difficult now than it was for previous generations and I don't buy the straw man arguments about generation y and its penchant for gadgets being entirely to blame.
They just retire from their job that's all. Still working on projects like hedge funds, building the next realestate.com.au in other countries etc.
Gen Y definitely spend more. At the very least, they travel a lot more than what my folks did when they were in their mid 20s.
Another poster and I are planning a Europe trip next 2 months and maybe a Asia/Japan trip at end of year. The first time my mother went to either was when she was over 40. Same with my father.