Honestly I don't think the issue here is the time taken for mats to be grinded I think its how incredibly boring farming for those mats is. Personally as somebody who gets constantly told to grind and do my Nyx quests I can say the reason I don't and the reason you cant just tell 30 people to go and do their Nyx quests and other types of grinding so their town can pvp is because its incredibly dull.
TLDR: Clicking block people is fun. Clicking block animals is boring.
TLDR: Clicking block people is fun. Clicking block animals is boring.