Hm, on the one hand this could be survivorship bias, i.e. only a lucky few scripts in stone have made it through. If you left enough of these glass discs or other modern media in very specific conditions they might also withstand thousands/millions of years maybe?
On the other hand, I think the amount of data and the corresponding resolution is important, too. If you'd try to store petabytes (or more) worth of data you'd have to carve really really tiny scriptures into stone unless you want mountains of stones just to save some bits of data. But the moment you scale your resolution up and your data engraving gets much smaller, you'll also get a much more error prone, susceptible system. So even stones with tiny scriptures would certainly not be able to survive millions of years (at least the vast majority of them).