For example, if one or both of them prioritize their careers over their marriage, and spend no more than an hour or two a day even in the other's presence, let alone quality time, for years on end, because they're busy at work or with something else...it's entirely predictable that they grow apart. That was the failure. They chose economics or the corporate ladder or an app that's changing the world or...over their marriage.
To you. But not so for many people, i imagine. I think the rate of divorce in America would suggest otherwise. Not to say that those are all healthy individuals, but that description sounds like a very religious-centric outlook on an often secular behavior.
In this framing, i'd argue that the liability of marriage should be thought of as "until death", but still. Sometimes the person you become is not something to be accepted nor desired by your loved ones. So who is to blame?
Do you change who you are? Or does your loved one change what they love? Sometimes both are unfair questions.
People don't just become incompatible. Something went badly wrong for that to happen. It's increasingly common nowadays - nuclear families tend to be more atomized, rather than integrated into an extended family, which increases the stress on the relationship, and many people simply don't prioritize their marriage, but instead their career, kids, or lifestyle. And of course, the modern social environment is more full of distractions and temptations than ever.