A look behind the curtain: How are old bottles turned into new ones? (Short video)
It'll always be better not to use something disposable in the first place, or to then reuse it, but recycling certainly beats just landfilling perfectly good materials. The technology that allows us to recycle glass has improved a lot over the years, to the point that we can pretty much pour old bottle on one side of a recycling plant and have new bottles come out on the other side (well, not literally, as different parts of the process will be done in different locations, but you know what I mean).
NPR produced a kind of mini documentary video showing how it's done. Check it out: