I can't say our first few years of marriage were easy by any stretch of the definition. We struggled with a variety of issues - sudden death of her father, back to back deployments (her and I) and the general stresses of marriage and the military. The first 2 - 3 years were the most difficult but once she decided to separate marriage became easier. Then I separated and marriage was blissful - now that I work from home we have afternoon delights.
Back to reality, there are also issues of finding yourself/ourself; on our own and together. The younger versions of ourselves are shells of what we've become together. Marriage is never easy, regardless of when you choose to get married; 20, 30, 40...
Younger people divorce quicker for many of the reasons mentioned throughout the post but my belief is they quit through the hard times as they have an unfounded belief marriage is easy and without growth individually and together. We stuck it out through all those hard times; in part because we were the only constant in our lives as we moved overseas. Now in our 30s we understand and react better to those times life throws us a curveball.
Don't be envious, but do view marriage as a partnership through life - not a financial decision.