In the whole time that meal selection has been "gone online", there have two exceptions:

1. If you bought a ticket in a cabin that has a meal, and you bought it within the 30-day-to-1-day window, then at reservation time you could pre-select the meal.

2. If you were able to check in before T-24 (presumably due to a connecting flight before the flight with the meal), you were able to select the meal during check-in.

I know of no other exceptions online. (There are workarounds such as calling or tweeting.)

The reason these exceptions have existed is because they're totally different aa.com pages. The meal selection disappeared when AA redesigned a bunch of pages, but the pages they redesigned didn't include the reservation options page and the check-in page, and so the meal selection persisted there (but only available to those in these particular situations).

Now, as to when it comes back to the point where you can do it anytime (30 days to 1 day out) online: Originally it was expected back "in November". There aren't all that many days left in November! But I don't have flights where I'm up front booked at the moment, so I can't check myself. However, I would except the main thread on the sbuejct:
to light up with posts if someone suddenly noticed it back.