They're probably drowned out by all the times we click the "not useful" link on error dialogs

I haven't seen too much evidence that this has helped, but most of the ones i report are for sharepoint and access. I know when you respond to these links on KB articles it can take 30 - 90 days for the correction to be published, so i don't expect anything until the next version or two.
The crash reports have allowed them to identify a large number of bugs, with fixes pushed out either as updates or released as hotfixes. During beta tests the crash reports are responsible for many fixes. A large number of things fixed by SP1 are the result of reports returned soon after RTM.
When the error report asks to send more data, they are still investigating it. When it doesn't send data they have enough info to identify the cause. When (or if) they fix it is another story, but they do fix many of the bugs they identify.