It can take years.
Not all owners are on the internet & cars are still popping up once in a while.
The very first T/A broadcast I found was in my own T/A & was for a different T/A. It sat in a filing cabinet for over 12 years before it was claimed.
That was 19 years ago, the very first item I ever had claimed. Over 400 hundred more since then, but I have not counted the items others had like engines & transmissions that have made it back to their cars.
There have been quite a few though.
The more people that register & / or report what they have found, the more often reunions can happen.