Will I be able to watch my stuff in the future?

[Albertosaurus Rex]

That's a pretty vague title, so I'll explain myself. My grandmother recently came up with some old films; we're talking about those big rolls of tape in a tin can from the sixties. Obvioisly, very few people today have the equipment to actually play these things, and my grandmother didn't have anymore. Luckily, my dad found a store where they transfer these films to DVD, so he brought them there and we got to watch some old videos starring my father as a toddler.

The point of this little anecdote is that technology is changing faster than ever before. Those big tapes eventually gave way to things like the VHS, which gave way to DVD which is being replaced by BluRay, which will probably be (I'm quoting somebody else here) "the last physical media we will ever see." I will proably be able to play DVDs for at least 10 more years, but after that?

Likewise for gramophone records, casette tapes and CDs. And as anyone who worked with computers for a reasonable length of time knows, the older a program is, the less chance of getting it to work. It might be a program made for DOS or an older version of Windows, or a game for a discontinued console. Sure, there are emulation communities, but you still have to jump through some hoops. Likewise, some file formats are no longer supported.

And now there are are e-books. Aside from just liking the feel of a physical book, I am sure you can see where this is going. It all makes me a little nervous. If I buy any entertainment product (film, tv series, e-book, etc), how long will I be able to use it? In the case of books, I'll keep buying physical books for as long as possible, but are my DVDs going to be worth anything in the future?