Flash drives are not a lasting medium. You'd need something like a quad-layer blu-ray, which is not cheap and has slow read speeds compared to solid state storage. Also nobody has blu-ray readers anymore. Also blu-ray publishers are tiny. Also the expense of distributing physical media.

So we've arrived back at the beginning - you can have this cake and eat it too, but you're going to have to eat the expense yourself. Imposing it upon the entire consumer market is selfish and wasteful.