But they heaped on BD+ VMs, Cinavia watermarking, BD-ROM Mark, basically threw everything they had at the problem and hoped that something would stick. Movie studios actually say that Blu-ray supporting more DRM methods was actually a major reason they chose Blu-ray over HD DVD (which didn't support BD+, which supposedly was DRM designed to last a decade).
And again, if that perspective were true, the movie studios wouldn't have done the whole dance again with HDCP 2.2, BD+2, and AACSv2 when 4K Ultra HD Blu-ray came out (only for all of them to get broken again not long after release despite being completely-fresh implementations). You already needed the older versions, right? So, I would argue, it's actually a mixture of both.
It's funny, songs are much easier to share than movies, the files are a hundredth the size, yet the movie industry thinks DRM is very important while the music industry survives just fine without it.