Work to do what?
> But a person used to be able to graduate high school and get a job that could support a house with a yard, a car, a non-working spouse and children.
Why do you think this has anything to do with tariffs or manufacturing?
> How do we get that level of prosperity back?
Better pay for the jobs people actually work. Reducing inequality by preventing the richest 0.1% from capturing all the massive gains in wealth the US has seen over the past few decades. Removing regulations that prevent the country from building housing and therefore driving up housing costs. Switching to a healthcare model in nearly any of the comparable developed countries almost all of which deliver better healthcare at half the cost. Not expecting everyone to be able to live a completely unsustainable suburban life. Having the government support children's upbringing by paying for high quality education, instituting rules and regulations that require mandatory paid maternity/paternity leave, etc.
Lost of poorer countries manage to do this and more just fine. The US is far richer than most of those countries.
Very little of this has to do with manufacturing jobs falling from 18mm to 13mm.