Here's the postulate: Glitch would be better if player interaction were increased.
Based on that idea, if skills only depended on the previous level (i.e. AK5 on AK4, and RK on AK6), but not across "stacks" - not Saucery on Cooking, etc. there'd be more room for player trade.
At the moment, in order to be able to need chunks of rock, I have to know Mining I anyway. Why not just be a mining/alchemist, and to hell with the rest of you.
Likewise, Tinkering V still needs other skills in order to make certain tools, usually the skill it takes to use the tool.
What I'm saying is that there are game mechanics that encourage Glitch-as-island, and discourage interaction between players. Let the crafting chains stay as they are, but let the skills and skill requisites to perform crafting loosen up so that it's more reasonable to be a specialist.
And by more reasonable, I mean both "than a generalist" and "than it is now."