Declining usage of alcohol is one of the major reasons of declining birth rates and an epidemic of loneliness in white countries.
If the bar was the primary Western common area ("Where everybody knows your name..."), then its disuse leaves nothing to replace it.
Life... uh... finds a way.
Even now in the Korean-American community, the running joke is that if one suddenly starts going to church in their 20s, it's only because they're looking for a romantic partner.
(people keep forgetting how much reducing population growth and teenage pregnancy has been an explicit policy goal for decades! Getting it down to replacement rate is good, now we're arguing about the other direction needlessly)
About children the case is quite obvious. We created the cultural environment in which children are considered no less human than productive members of society and deserve if not the same amount of resources, then more. This order aligns well both with Western worldview and with human biological nature, so people are easily accepting and strengthening it.
But if we are spending on a child as many resources as on productive members of society, that means for fertility rate 2 we should forgo half of our resources. So on average to forgo half of your work for children are not very tempting, but to spend on children less is sociocultural unacceptable. The only solution? Less children.
I think fertility rate 1.5 is already pretty high for such environment and only show how strong biological drive to procreate for humans is. And government's attempts to increase birth rates by spending more seems like rather terrible idea: that only will increase cultural expectation on children costs and effectively will lower the birth rate even more.
Some counter theories: People have fewer kids not because they drink less, but because children are extremely expensive, wage growth has been stagnant, women make up a larger share of the workplace (and don't want to lose their spot), and birth control is more readily available.
People are lonely because: women are capable of larger roles in the workforce and it's upended social expectations, therapy has caused people to avoid others that they deep destructive/negative in their lives, technology has caused us all to be alienated, or society has shifted but culture hasn't caught up to these changes (assuming they're lonely at all and not just experiencing the same existence previous generations did but now with constant news cycles and the ability to tap into 24/7 feeds of people having fun).