> 2) End the spiraling healthcare costs (adding a single payer would likely go a long way)
Obamacare was introduced just before the US healthcare system would go into the red (be a net cost for the government, as opposed to a source of income) and delayed that by creating new income for the government. This was not a coincidence.
The whole purpose of Obamacare was to make healthcare less expensive for the government, by putting more of the burden on the population, without being a new tax. It is very far from an accident that healthcare costs have spiraled.
But Obamacare only delayed the government budget drain until somewhere between 2018 and 2020 according to the congressional budget office. So "Obamacare 2" is coming in the next president's term, don't worry. It might even have single payer, as obviously raising costs is not a compelling public message.
But it must raise costs. There's no other option. It must raise costs to get back into balance, as the US government has borrowed massively from the healthcare system and is in no position to pay back any of it, so it cannot be allowed to have more outflows than inflows. The consequences would be too great. Well, actually, unlike most of the rest of the world the US could choose to defund the military to a significant extent and actually get a few more years of healthcare out of it (but we'd be talking 10-20% budget loss for the military at least, and as you point out that would rob more than a few young people of economic opportunity). But it would only delay matters, it can't solve them.
What can you do ? Nothing really. Too few people paying into a system with too many dependents. More kids was the answer, but obviously those would have had to have been born 20-25 years ago. Right now, more kids would only put more load on the system for the first few decades. Massively opening up immigration could work in theory, but if Europe is any indication, it won't.
Of course, all of this is assuming there won't be an economic crisis, and at this point, we're overdue one.