I think it'll be the exact opposite.
Instead of having a conglomerate of kingpins controlling the MB as a whole loosely. You'll have to face just the one kingpin controlling his own little section with an iron grip. Because he can focus his efforts better than a group can.
A couple weeks ago, I noticed a price war between 2 people on the mcD market on Jenova
where the prices just plummeted from 400k earlier that day down to 150k in the course of about 2 hours.
That's probably because those two were "specialized" in that market and didn't have any other diversification and hardly any competition, it was literally just the two people undercutting each other to hell. When all was said and done, prices went back up again to 350k so it didn't really do much for the buyers.. It just made it harder for other sellers.
Do you think you can compete in that kind of hostile market?
Maybe my concerns stem from the size of my server, most end-game items only have 3, 4, or maybe 5 sellers. If there were more crafters, all my concerns may be alleviated.. But I just don't see Jenova's population problem changing any time soon so there's really no point getting into that discussion..
Oh and also,
if you have 3 lucis tools, you're not a mid-tier crafter :P
You may happen to compete in mid-tier products because there's more demand and it's more lucrative.. but you're still pretty high up there
