Do they? Or are they just suffering silently?
On the obligation of adulthood, do you mean to say that starting a family is an obligation? If so then I wonder if perhaps people choosing not to do so may not be a bad thing. My parents married because that's what you're supposed to do as an adult, and it was something I know my mother regretted later in life. Some people start families and rise to the challenge but it's tragically common that they utterly fail as well.
600,000. That's the number of unique cases the various Child Protective Agencies in the US contends with each year. The US CDC estimates that 1 in 3 women will experience violence committed to them by an intimate partner, and 1 in 7 men will experience the same. Unhappy partnerships aren't exactly rare.
I suppose that does beg the question if it's better to have fewer families with a higher portion that are stable, or more families in general even if it means a higher proportion of them will be broken or unstable.
Life is short and I've got shit to do and places to be, I ain't got no time for that concentrated bullshit.
The downside is that in a society where that isn't an option people are forced to socialize and then they adapt. Having everything catered to shut-ins normalize pathologies, something common across a lot of modern internet subcultures.
It enables a sort of Peter Pan like existence in which people stay perpetual kids without ever having to take on the obligations of adulthood. And it's becoming so common that in countries like SK who are at the front of this people have replaced starting families and having sex with adopting dogs and cats. In an entire society like this who takes care of them and delivers their packages when they're all 60 years old is a frightening question. (and a very real one in the near future)
If it was an odd-ball thing it wouldn't matter, but social isolation and delaying or ignoring responsibilities adult social life are now mainstream issues.