It doesn't currently make any more game sense to specialize than it did to do anything but (for instance) munch Rookswort all day.
So long as I can be as good at everything all at once as someone who specialized in any one thing, then it will pretty much always be easier to do all my crafting myself. The only value to be had in crafted/collected things will be the convenience of having them in 10 minutes, versus the iMG/enjoyment of making them yourself. (And frankly, I'm not sure if there's many things a dedicated player couldn't make from scratch in 10 minutes at the moment.)
The flip side of the "bonus/penalty" coin would be: what if the bonus you get now from your skills was just what you get if you're at or above 100% brain capacity? But if you were under capacity they up-to-double. So if *all* you do is Mining, you get the bonuses of Mining IV almost-doubled - i.e. mining takes you 2 seconds, and the chances you find a gem are almost doubled. So you'd be a rock-chunk *machine*, and you'd only ever donate gems, but totally reliant on others for food and cocktails and tool repair.
I think that'd rock (heh) but if you don't, then ignore the extra bonus and be a JOATs and continue as your are.
But right now, there's no game incentive to cooperate - it makes much more sense to do pretty much everything yourself. At some point someone will work out the absolute fastest queue to learn all the skills in and anyone who plays for - 3 months, 6 months? - will have all the skills, and it's a solitaire game with chat and parties.