marriage is never a simple matter. but you are right that people's expectations have changed over the years due to changes in social norms, media, etc. i find more and more of the younger generation are more self-centered and crave for attention. hence the problems you have mentioned. ola's points may be quite simplified but i think he has basically has them covered.
in fact some may not even need their own flat or stable income. a few weeks ago the new paper had a story of a malay man who left his family, and an indian woman who i think did the same. anyway...they found a spot along the kallang river and called it home. they also found love there.