Because they weren't invented in 1925? Any durability testing you do today is about assumptions where you accelerate the process for a year by heating it or exposing it to water or whatever will degrade it most to some factor above normal and then extrapolate. That extrapolation was wildly wrong with CDs and it could be with this medium too. Or it might last a lot longer. What they have not done is written to a bunch of them and stored them in a variety of ways for 100 years and concluded they last that long.