Hilariously, DVD production could potentially outlive Blu-Ray discs, since DVDs are still popular enough 30 years later, and surpass the sales of Blu-Ray movies.
I spoke to my local librarian who cited this as the reason they haven't bothered with 4K blueray despite it being 10+ year old technology at this point.
Think of it from the point of view from senior citizens. They likely already have the equipment for DVD and are used to it. That alone is "simpler to operate". Yes Bluray could often have simpler menus but that existing inertia is something that is important as well because I dont think most senior citizens are actively seeking out newer tech if they dont need to.