Just in case you find this information useful: there's `pdftops` and `pdf2ps`. They are not the same. This answer refers to the former. `pdftops` is part of the xpdf tools, as well as its fork, poppler. Poppler's broken in the package manager, so I used xpdf. It produced a fully rasterized _low-res_ output and I couldn't figure out how to increase the resolution.
Then I went to Ghostscript, which produced better output and I could control the resolution, but it was still rasterized.
Finally I gave in and manually converted one-by-one using Acrobat.