I hate these bags and have outsourced in the past.
For koozies though, I do lots of small runs (10-25 sometimes) and offer overnight or even same day turnaround on common colors (I usually have black, burnt orange, red, and a handful of others sitting around). If someone orders 250 or 1000, sure outsource away, but that isn't always an option if you don't want to tell someone "No!". They might end up paying $8 or $10 bucks a koozie, but if it's something they really want, they will do it. I dont mind making 100 bucks for 20 minutes of work and 5 dollars of materials.
...but those bags, UGH...they suck terribly to print and cure.