So how long do you think Trump is going to keep this temper tantrum government shut down up?
At least until after New Years, I'd say. Of course, on January 3rd the new Congress takes over, and then there's zero chance Trump gets his wall...
I could be glib here and say, "Never underestimate the ability of the Democrats to capitulate," but there are two reasons (that come to mind) they might give in (at least somewhat) on this, and they both have to do with who gets impacted by a protracted government shutdown.
1. The markets always take a hit when the government shuts down, and that impacts rich people, including political donors (both to Democrats and Republicans, though, so this might be more of a wash since there'll be pressure from both sides).
2. Many of those federal government employees have to work without pay, to be paid later, or just get furloughed and never get paid for this time--thus losing income (even if only temporarily for some). That's big, considering how many families in the US can't afford an unexpected $700 bill (or even $400), which is essentially what "not being paid for a while" amounts to. And a lot of those workers are in unions, and so those unions will put pressure on Democrats to end the shutdown.