Nah she won't make it, but even if she won it would've been hit and miss. But yeah, certainly could have used those 8 points.
What matters most is that I am fairly certain she'll probably get in to the Aus Open qualy draw on her own ranking as she as pretty much jack all to defend the rest of the year Hopefully she can set herself up to get into the qualy draws of the other Slams next year. So if she misses out on the US Open this year, I don't think it's such a big deal - she should use this season as a building block for a better 2007.
I don't think she'd be injured (bloody hope not), but perhaps she wanted a bit of a break. She may have realised she missed the cut for US Open qualies, so decided to have a rest. I still think she should turn up to Flushing Meadows anyway, and try her luck as an alternate. You never know.