Since Sony was mainly behind the Blu-ray format, I'm very surprised they didn't become more innovative with hardware level protection, like they did with the original PlayStation. E.g. remember the black game CDs?
Just an example - use a non-standard disc size, e.g. 14cm with higher capacity and reading starting from the outer edge in.
Another option - have a triple layer disc, i.e. first two for blu-ray and a 3rd deeper layer for authentication. Either this or another type of CD for which there is no recordable equivalent of.
Alternatively - Bring back the game cartridges. They also had the advantage of being very robust, especially with children.
Sure, someone will manage to develop a mod chip to counteract these measures, but at least it doesn't have this flaw where a key leak compromises the whole security.