Thanks Bluntness and yes I think you have good points! 
Also, as dowagercuntess said
Out of DH's group of buddies, one is still single, aged 40. He doesn't have the old group to go out with every Friday and Saturday night anymore. He's latched into some younger work buddies, and is on tinder or whatever the OLD sites are called. He's got a few more grey hairs. They're thinning, and the crows feet and other lines are evident. He lives alone in a half-renovated flat, quite a way out of central London. It's not a life I think any of his mates envy.
This 100 x over. Me and my husband know a few men like this actually. (All of them are 38-44 y.o.) A couple of them were married and divorced before 30 (no kids,) and 2 or 3 of them have always been single. Same as dowger described; hanging onto their youth, going out every Friday getting pissed and acting like they're 19, and poo-pooing and ridiculing any man who gets married. Yet they live in tiny grotty flats, have old banger cars, never go on holiday, never go anywhere, (other than the pub,) and have been wearing the same clothes for years.
Upshot is, with men (and women really,) life is no picnic if you're single and poor. If you're solvent and fairly wealthy, (mortgage free perhaps, a six figure sum in savings, a healthy pension plan etc,) being single is fine, but if you're quite poor, it's not a great life for most.
Virtually everyone I know who is poor and a bit destitute, and who can barely afford to top up the electric meter, is single. I know very few poor couples. I mean, plenty of them aren't super wealthy and do struggle sometimes (especially if an unexpected large-ish outgoing comes along,) but they do manage, and they do cope. They have the odd pub night out, the odd holiday, a decent car, and a couple of hobbies each, and a decent quality of life.
This is due to double income (usually,) and having virtually the same outgoings as a single person. I would take being married over being single any day of the week, and my husband says exactly the same.