That is true for all media purchases since the invention of copyright in 1662.
You think you own the Silmarillion because you have a paper copy? Hah! No, you have a transferrable license to read it.
Every hard copy movie you have starts with a big green FBI warning reminding you that having that disc does not means you own the movie, it means you have a transferrable license to play it for yourself and small groups on small screens.
Digital media with DRM allow content distributors to remove the "transferrable" part of the license if they want, which often allows them to sell for cheaper since they know that each sale represents only one person recieving the experience. The license comes with less rights (no transferrance), so it can be priced lower.
Most media for me is a one and done. A book, a movie, a computer game. Granted a computer games version of "done" might mean "played on and off for a year".
There are exceptions to this - books I read again, shows I'd watch again, but games seem to age poorly by comparison. Original Syndicate or Deus Ex - while playable - is not what I remember it to be and I'd rather keep the nostalgic memories than shatter them with a replay.
This rarity of exceptions means that I wouldn't lose much if my Steam account disappeared - mainly just "whatever I'm playing now". Create a new account and go again, or buy off GOG or something.
However in return for using Steam I get a lot of convenience - updates, propogated save files, easy chat and "Right click -> Join Game" with friends. That "Right click -> Join Game" is almost worth it on it's own for ease of social gaming.
I would like to see change there for sure. That said, DRM is optional for publishers on Steam. Once you've downloaded a game without DRM (steam's or otherwise) you can back it up and play it without Steam.
