There are in fact long lists of things that we as people buy regularly--things which we "own"--but which are used up very quickly to the point that we must always buy new things to replace them:
These things have a material value which is easily quantified, something data lacks entirely.
You don't own anything on Steam. None of it. Valve owns the servers which serve you your license to use software, software that is owned wholly by the publisher/developer of said software. The fact that software/movies/music used to be sold on a disc, in a box, with MATERIAL VALUE attached to them meant the purchaser owned them. Not in the strictest legal sense, mind you, but nobody would go out of their way (until now) to try and stop you using/redistributing that disc and box however you saw fit. Steam has completely removed the physical component and, with it, removed the apparition of "ownership" from the equation.
And no, piracy isn't the only option. The option is to wait for the price to come down, which is what many of us do.
Steam + PSN: PHJF