The short answer is we dont' know. A vaccine is an 18 month proposition. And while maintaining these measures long-term doesn't seem like an option, neither does having to burn bodies because there is no place to dispose of them. According to the Wall Street Journal, the death rate in Lombardy, Italy is currently standing around 5%. There's probably some asymptomatic people that they're missing, but that's what happens when the hospitals are swamped.
Worries about 6 months down the road, or an economic stimulus package - all of those are completely the wrong worry right now. To use the appropriate metaphor, when a person has been shot, you don't worry about the infection they may develop a couple days down the road - you deal with the fact that they're bleeding to death.
Watch what is happening in Wuhan. They shut the area down for nearly 2 months. They are gradually starting to reopen factories right now, which will probably trigger other transmission and infection. But, if they keep it at a manageable rate, then the death rate stays down.
We may get lucky and get a reprieve from heat in the summer, but we don't know enough about the bug to say yet. There have also been some unconfirmed reports of people in China getting sick more than once, which could imply that building immunity might be difficult as different strands start to circulate.
There's a reason the stock market plummets every time we get a speech about the economic part of it, because no one wants to hear about that or care about it. That part doesn't matter until you stop the bleeding. Right now, the number of cases is doubling every couple days. We already know that some areas are about to be swamped by cases infected this week, we can't let the whole country have that happen.