The detailed answers by /u/Platypuskeeper and mine in the following question threads cover the reception of Vinland literature in post-medieval period (mainly the 19th and early 20th centuries):

• At what point in history did the Europeans realise that Vinland and Canada were in the same place
• Prior to the discovery of L'Anse aux Meadows, how seriously were Norse transatlantic contact theories taken?

Put it simply, academic historians, especially Scandinavian (including Icelandic) ones, in the first half of the 20th century under the influence of arising literary saga study school, had generally been not so enthusiastic about the historicity of Vinland sagas as well as Leif Eriksson. So, they viewed things rather different from [added] the popularity of Leif and the sagas in contemporary popular history scene, represented in the national day of Leif Eriksson.

On the other hand, as I summarized before in When did the Norse settlement of North America as being pre-Columbus become settled as a historical fact?, relatively swift and wide acceptance of L'Anse aux Meadows as a genuine Norse settlement in Newfoundland (within 10-15 years after its discovery) both in academic and popular circles mainly owed to the findings of a few Old Norse style artifacts.

In other words, what their discovery as well as the archaeological site itself validated is the short-term settling attempt of a group of the Norse people in the beginning of the 11th century in Newfoundland, neither the narrative of Vinland sagas themselves nor the historicity of their protagonist, Leif Eriksson himself. Concerning the deeds of Leif in medieval saga literature, you can also check my previous post in Can I hear about Leif Erikson, all I know about him is that he was the first important European to step foot in North America and I would like to hear about that and any other cool things he did?.

[Edited (2nd times)]: removes a typo; adds the missing sentences lost in course of copy & paste (sorry).