One note - most of these arguments revolve around poison.
Substitute any normal item for poison, and this becomes silly again.
A month to make a single longsword, at 8 hours a day?
How many longswords can you buy in a shop?
I've spoken to modern day smiths about this - they can do this in far less time, and they don't spend 8 hours a day, every day, working on things.
If it truly takes over a month to make a single masterwork weapon, how on earth do you equip an army with fine weaponry? 10,000 troops would take 100 smiths 10 years to equip! If that's _all_ they did.
Craft rules in 3e are just hosed. I dunno how to fix them - we typically just set a reasonable time and DC, and go from there (IE: It'll take 3 days to make that sword, and it's DC 28 to make. If you fail by 5 or less, it's 2 days more. If you succeed by 5 or more, it's better, or faster).