well, some of them are pretty trivial (life without shrinky-dinks is just life) but others are pretty major. when i started out writing this i didn't realize that plastics were essential to literally every way to record motion picture or audio data until the invention of hard disks
i did mention that, but probably there is some alternative. for example, you could directly selectively etch away a vacuum-coated metal layer with lasers or electron beams, perhaps even using a shadow mask. so i suspect that's more a question of how expensive the products would be rather than whether they would be feasible at all
