This maximizes returns on capital at quarter and even decade timescales.
This doesn't make sense. Governments want children and immigrants because they need a tax base to stay in power.
As for businesses, they want employees doing things that project stability, such as getting a mortgage (a lot of companies give off time to close one), getting married, and having children. People who do that don't rock the boat and don't speak up because they have a life outside of work they need to upkeep with their paychecks; so they stay good worker bees.
The various forms of collateral you mention (wives, children, mortgages -- the things the Mafia don would ask you about) have a carrying cost which companies would probably rather not pay. And with golden handcuffs (plus restrictive H1-B visas in some cases) the companies may have enough leverage without them.
> Governments want children and immigrants because they need a tax base to stay in power.
I don't think they plan that far ahead, because the electoral cycle is only four years long. It's like issues of national debt: You may have a momentary crisis, but you find some path of low resistance out of it (issue more debt), and keep going. That works because the rest of the world is happy (for some reason) to keep buying up the debt. Demographic issues can be papered over similarly, so long as the money -- the same money, ironically -- provides an incentive to come.
(It's also worth considering that, since Reagan/Thatcher (and arguably Carter, though in many ways he seemed like a good man), the State has lost power to the Corporation, so even if the State does pursue longer-term interests, it may not play a large enough role in day-to-day life to have an effect.)
If you're just following gradients, I think this is the basin you stay in. But it feels like some kind of behavioral sink.