Tools, opportunity, and a good social environment are largely a function of money, whether purchased via government programs or bought by individuals themselves with the cash given by the government (I.e basic income, EITC). Marriage alone without that money isn't going to avail those bootstrapping goods to people when they don't have them to begin with.

> are largely a function of money

Lots and lots of immigrants beg to differ. I will grant that you do need at least a good community, but you don't need money to get ahead.

That's why I added "social environment" - you need a community who help each other much more than you need money.

Membership in a good community is itself a form of social capital that you can even put an monetary valuation on (compared to not having a good community). Many immigrants arrive with that form of capital intact, and admission to such communities is often gated by cultural barriers.

Further, educated immigrants, while they don't start in their adoptive country with much money, arrive with a lot of educational capital, which someone invested in before they arrived. They arrive with the "tools and opportunity" built in.

For less educated immigrants, and native-born poor, assuming a functional community exists (which is not a given for either), it's members might be able to scrape together proceeds gained by expending their physical capital in marginal labor, and share resources among themselves (housing, childcare, etc.).

But depending on their circumstances, that may not be enough to move their members out of poverty, as the surplus of their labor may not be enough to pay for, in your words, the "tools and opportunity" needed to escape poverty.

Sometimes the requirements for the community's survival can actually hinder the acquisition of tools for advancement, i.e. a 16 year old has to take a menial job to help support the extended family instead of staying in school.