I've seen the name of the Bug Reporter webpage thrown around on these forums quite often as a way to get a problem solved... I've submitted several bugs in the past with instructions on how to reproduce them, yet I've never seen anything done with these submissions. Do their devs simply look at the page, and move on, or do they close these reports once the issue has been resolved?
Yes, they do look at the reports but they do not reply to all of them immediately.
90% of my bug reports were replied to, many asking for more logs or sending me a profile to debug my issue and so on. I would say the average response would be 2-6 months for me, majority were closed as dupes.
Often, the ones that exceed the 6 months are the ones where they are aware of what the problem is, don't bother saying anything and then follow up when a new version of OS X is released asking me to repeat the tests.
They just don't have enough people and time to reply to everyone's report right away, it is virtually impossible when you have thousands of new reports coming in daily.
Even MS doesn't do it in their Feedback tool during the Windows 8 and 10 development.