> Housing - build more and higher density.
Zoning is an incredibly hard science. Hardly any country on earth manages to get this right. Solutions are often also highly specific to local parameters. Though admittedly, the US has glaring issues with some housing areas being super spread out and low density outside of city centers.
> Healthcare - price transparency and make it easier to shop around. Incentivize frugality.
The problem of making healthcare universal and affordable has been solved plenty of times around the globe already. Obama's administration made a huge leap in the right direction, but there's more track to cover and issues to fix before the US's healthcare system becomes comparable to a say, European, equivalent. They never got the chance to finish this though.
> Education - stop letting 18 year olds take out $200k in loans for poetry degrees.
Generally having education governed by free market forces, thus giving the best education to the highest bidder, kind of goes against the US's slogan of (equal) opportunity. Not to mention all the other issues with that idea. Again, just copy any of the plenty of countries with a better system.
And don't give me any of that "But the US is a larger country and thus those solutions wouldn't work". What happened to divide and conquer? Just have administration sit at state level and you get to pretend the US is really 50 smaller countries - divide further as needed (some countries like Germany use this strategy to divide administration of their education system as well). Also there's plenty of countries with a number citizens in a comparable order of magnitude with working systems.