I think this may be true. After my last Mac upgrade, the app did not work with either of my phones. It looked like just a timing issue, because the files would eventually appear but the file transfer app had given up and wouldn’t let you do anything but quit. Probably a fairly minor bug that for whatever reason they just won’t fix.
As for the question of why, it’s certainly within the realm of possibility that they just don’t feel like maintaining it anymore.
I think this may be true. After my last Mac upgrade, the app did not work with either of my phones. It looked like just a timing issue, because the files would eventually appear but the file transfer app had given up and wouldn’t let you do anything but quit. Probably a fairly minor bug that for whatever reason they just won’t fix.