Has it come to the point that to truly appreciate D&D and gaming in general, a person has to read Lovecraft?
Yes and No
Yes, GMs should read his work to get at least a passing understanding to many of the "cult" icons you see appearing in the works.
Not so much with players, they can get away with just riding a good narrative. The GM can introduce most of the elements from his story into the campaign without the player having to know Lovecraft.