Adding guys like Whitlock, Slaten, Schreiber, Bernardino and Winckowski is not costly.
Dumpster dives like Hill, Wacha, Kluber, Richards and maybe even Gio are more costly and have been mostly unhelpful.
If our system of finding and developing young pitchers does not improve, or even if it does, we won't see instant results in a meaningful way for a while, we will have to add outside pitchers one way or another. Dumpster diving should just be part of that process, as hitting on some makes it worthwhile.
We need to invest in real talent, at some point- either by trading everyday players/prospects or spending big on a FA and hoping we don't swing and miss. I'm not sure when or if this happens, anytime, soon.