It is no longer functional on macOS 10.15+ because it is not a 64-bit application.
It was, however, still available in the boxed copy of iLife '11, until the release of iLife '13.
iDVD was no longer preinstalled on Macs shipping with Mac OS X 10.7 Lion, and was not available on the Mac App Store with all of the other iLife apps.
While initially available only for Macs with a SuperDrive, it was included until 2011 with all new Macs from iDVD 6 onwards, Apple supported the ability to burn projects with third-party optical drives.
