The Norse were bold explorers, ferocious fighters, and, when it suited them, canny merchants. They took and settled many new lands: the Shetland, Orkney and Faroe Islands; Iceland; Greenland; and they contributed in a major way to other lands, such as the British Isles, Normandy, and early Russia. Yet from the most promising land of all, North America, they soon withdrew in utter defeat, and never returned for any but the briefest incursions. Why?
It wasn't just that North America was already settled. The Norse had encountered that situation before, and dealt with it as needed - subjugating or negotiating, as the case might be. There are hints in the Sagas that they tried both in North America, to no avail.
It wasn't that North America held nothing they wanted. There was land in plenty, and timber, and furs, and some of the best fishing in the world, and much else that would have supported a colony - if they could have come in great enough numbers.
That seems to have been the primary bottleneck. Norse ships, though they were the most advanced and sophisticated of the time, were still relatively small and ill-suited to long voyaging on the open seas. It was impractical to bring colonists and supplies direct from Norway, and none too simple to bring them from Iceland. That meant Greenland had to be the primary source...and Greenland itself was scarcely settled at all, with a small and resource-poor population. They could, for a short while, manage small exploratory expeditions, but drawing off the personnel and resources for a major settlement was out of the question. Even resupplying an expedition from Iceland (or Norway via Iceland) would have been a severe strain (and this was never attempted).
So the Norse came, looked around, wintered over a time or two, and went away again. And Norse Greenland, always marginal, withered and died in the chill of the Little Ice Age - when everything they needed to survive was only a short sea voyage away, a voyage they could not afford to make.