It's said in Star Wars: The Force Awakens that Luke Skywalker exiles himself due to the failure of his Jedi Academy.
Training some new jedi, one of his turns to the dreaded Dark Side. His own nephew. Some/all the Jedi besides Luke are killed as a result. This begs the question, why did he run? he faced the Empire, as the sole jedi, why would he abandon the Republic, his sister, his friends, while one of his students was on a rampage with a Dark Side master?
We dont know who or what Snoke is. Vader took it easy on Luke, because he had doubt in the dark path he took. Sidious played with Luke, zapping him sweet nothings. Luke has never faced (in the new canon of course) an actual darkside master at full power. Snoke may not be a Sith, but Luke isnt a full fledged jedi. He got a hodge podge sort of training. Everything else he sort of baked up on his own.
So my conclusion is hes facing a legitimate threat with Snoke, and went away to find knowledge to improve his power. The Jedi purge left him with no masters to train under, sans the two who did what they could for him before they died. An old Jedi Temple, untouched by the Empire is the only logical answer. It was ingenious for Lucas to rationalize the more epic, fast paced Lightsaber duels as a result of the loss of teachings after the Jedi Purge, and the decline of the surviving masters. Luke had a very rudimentary education in the Force and Lightsaber forms. I mean lets face it; Clone War Era padawans had a better education of the Force than Luke.
The Jedi had arrogance in their ways, assuming themselves too powerful, or too well seated in the galaxy to be wiped out again. They were, after all, in their peak. Sith were cleverly concealed with the Rule of Two, so their teachings were, in fact, reasonably safe.
The Rule of Two is a Sith tradition that says only two Sith may exist at once. One to embody the power, and one to crave it. This reduced the inward fighting to a minimum, and cemented the tradition that every Sith was stronger than the last.
Again, I do not think Snoke is a Sith, however I do think the Darkside had much more abundant ways of preserving their teachings. Nobody went around purging their texts because everyone thought they were extinct.
Luke's best shot was to disengage, and gather more intelligence. Yoda was gone, same with Obi Wan, but their spirits could still guide him. Perhaps they suggested for him to go off to find a world untouched by anyone for thousands of years, in order to gain the advantage needed to take down the enemy. After all, it wasnt the Jedi way to full frontal assault your enemy. It was much more prudent to take them down using knowledge and understanding, rather than brute force (pun fully intended).
Let me know what you guys think, I of course am going off of what I know of the canon, and even some of the noncanon references to the Jedi and Sith to come up with this conclusion.