That's an excellent question. The answer I would give is that the process by which the Norse settled Greenland did not actually ultimately work out in the first place. Colonization isn't a simple matter of gathering enough people to form a colonizing party, staking out an empty(-ish) piece of land, and building a new settlement there. Once that settlement is built, there needs to be a steady stream of consumable goods being provided, and until the new settlement can produce or trade for those goods on its own right, the colonizers are effectively subsidizing that settlement.

The settlements in Greenland never really reached that point. The leading hypothesis at this point for why Greenland collapsed was that the Arctic trade routes dropped far-off Greenland from their destinations--and without that trade, the settlements couldn't sustain themselves and collapsed. Newfoundland may be a more hospitable place than Greenland, but from a trade situation, it's even worse: it's not offering any trade goods to Europeans that Greenland or Iceland could be providing (at much shorter journeys), but it's still probably not able to tap into the North American trade network--I think you have to make it to Nova Scotia or New Brunswick to do that.