I also found that they seem to value the tradition and style (quality of food, quality of dinnerware, quality of decoration, etc) much more than the company.
Before marriage, we (guys) would get together often. After marriage, it promptly stopped. And the accounting began.
As I said in another comment, the causes of the decline are plenty, and nothing really dominates. I've given a few reasons here and elsewhere, but I'm sure there are many more. It's a death by a thousand cuts. The reasons I give here are due to a certain sub-clique. It won't apply to others' experiences.
In my family, not surprisingly it's the wife who wants to host dinners. And because of the (IMO) high standards, it means she's missing for days to over a week. Life pretty much goes on hold in the household during that time. She can't watch the kids, so I have to. We both work and have little time, which really means the kids get neglected - and it's measurable.
If they lowered their standards, this wouldn't be a problem. But they seem to value those standards more than the social mixing.
If hosting was "simple food, no decoration, not the tidiest home", it would happen a lot more.
(Of course, if you host at a restaurant, that's the most expensive).
Little confused by your example. Your wife hosts (let’s say on a Saturday) but prepares for it all week and doesn’t help with kids? Is that right?
And that may be why restaurants are out - kids are bored at restaurants.
> Your wife hosts (let’s say on a Saturday) but prepares for it all week and doesn’t help with kids? Is that right?
I'm saying it takes both of us to properly parent the kids, because we're both working spouses. Kids only get 3 hours at home on weekdays. In that time you have to ensure they get food, do homework, have fun, and bond. 3 hours just isn't enough when they're young kids. If one parent is absent, the debt grows.
My point (scattered across various comments), is that socializing need not be hard, and inviting 2 other families for dinner shouldn't take days of preparation. But because of the all the ceremony and effort that people (needlessly) put into it, it does. If they want more socializing, lower the standards. Just have simple food, no special setups, etc.