Problem: While this is all very profitable, it presupposes a few things. The previous conversation was starting low level industry with available resources, including manpower.
Bear Island does not have the people to do more than basic subsistance farming off limited arable land, if it possesses any. They could probably feed their entire island with more arable land if we produced it via earth formation, volcanic ash from SotD, but they would have to turn over every stone and pull away fishers and the like to start exporting grain.
They have enough people to man perhaps several ships, and that's probably by dragging away everyone else already working a small fishing ship or boat. They could do basic resource trading like furs and the like, but setting up mining enclaves? Ice cutting and shipping?
This is all extremely labor intensive. They could just barely afford, in manpower, with skilled trainers from Ibben, afford to man one, maybe two but that's stretching it, whaling ships.
It would take at least three generations going full-bore with access to ample food before they could start working several ships without pulling away too many people from other economic activities, four before they could start establishing a permanent presence north of the Wall.
Bear Island as a whole doesn't make sense and shouldn't be poor. It's huge, approximately 200 miles wide east-west and 150 miles north-south. If we take the smaller measurement as reflective of its actual size and estimate it as a circle, it comes out to at least ~70,000 square miles. For reference, that's almost
twice the size of Newfoundland or Cuba. The island is described as being warm enough to have
oak trees on it. That means that the temperature can't be
that cold (perhaps slightly warmer than Scotland, year round?) because oaks do not grow well in the cold. Additionally, oaks require
significant and fertile soil in order to set their roots down. This tells me that Bear Island should have more than adequate soil to grow its own food as it's deep and nutrient rich. It's at the same longitude as Last Hearth and the later is described as having difficulty feeding itself only in the harshest winters.
If anything, this tells us the Bear Island should be
more populated than a comparable slice of Last Hearth. Bear Island is renowned for its sailors and the frequency with which they go to sea. People can farm during the summers and then when winter snows stop it, they can fish; the people of Last Heart starve or resort to cannibalism. The people of Bear Island fish often enough that they ended up leaving their wives vulnerable to Ironborn raids and thus engendering their ideals of warrior womanhood.
Additionally, only setting up colonies in the Frostfangs is really manpower intensive. Cutting ice from the Frozen Shore would be no more difficult than fishing in those waters and it doesn't require extensive equipment. Ice was preserved in the past by stuffing it in ship holds filled with sawdust. That's all that's really needed and we know that Bear Island has sailors, ships, and sawdust; and every ship should naturally carry axes and saws, so it could cut ice. Trading with the Wildlings wouldn't be manpower intensive either. All that you would need to do is reassign a few of their fishing fleet to trade instead. Longships and other, comparable vessels like sloops can carry cargo to trade or fish. Given how reluctant the Wildlings are going to be to trade, it's likely you'd only need a few ships anyway; a single ship can carry tons upon tons of cargo.
Lastly, when it comes to manpower, Bear Island has a significant advantage: their women are trained to fight too. This means that they have
double the regular reserve of manpower and their colonies would be extremely hard to attack for that reason. They'd still need to source miners and prospectors from somewhere, but given its size, Bear Island should have some mining, even if it's not famous or renowned. Iron is heavy and hard to move so sourcing it locally
drastically reduces the cost and iron is wonderful because it's extremely common. Realistically, of all of these options, only the colonies are difficult to set up.
If Jorah Mormont had been smart, it would've been fairly easy for him to set himself up for success, even if Bear Island is as poor as it's purported to be, despite common sense. After Balon Greyjoy's rebellion, Jorah was a war hero and he had Robert's ear. If he asked for royal funds to set up a fleet in Bear Island to counter the Ironborn, he would've gotten it. Robert was always a spendthrift and it makes sense for the North to have some type of navy on the west coast. It's necessary to counter the Ironborn and the Wildlings who raid the island and past the Night's Watch. Using the money to set up major harbours, timber extraction, iron mining, charcoal burning, etc.; and then using that to supply the fleet would have allowed him to build up extensive local industry, manpower, and military force. Setting aside the likely hundreds of thousands of Gold Dragons Jorah could've gotten from Robert (we see Robert drop at least 100,000 Gold Dragons on a frivolous tournament), it's likely that Jorah could've gotten additional funds from Ned Stark as well. That's still setting aside any money he could personally raise and the loans his Hightower father-in-law would likely give him at a good rate.
Money was not an issue if Jorah was intelligent (he had tons of money, he just spent it foolishly) and it doesn't make sense for manpower to be an issue either.