"And, as Luke puts it to Rey, it is Jedi arrogance that assumes that the fate of the Jedi order is identical with the fate of the good and the true. The Force is in everything, binding everything together, and the Jedi do not have a monopoly on it.
All this, along with his own failures in trying to reestablish the Jedi order, is what leads Luke to the conclusion that he must die and the Jedi must die with him. He wants to burn the past. In this way, while Luke has been described in this film as a kind of John the Baptist, he is more of radical reformer of the Jedi order. No greater act of iconoclasm can be thought of than to burn the sacred tree and the sacred texts
By the end of the film, though, it seems as if Luke has reached a new insight. Rather than simply burning the past in an attempt to forget or erase it, he tells Kylo that in fact Luke Skywalker will not be the last Jedi. Some trees need to burn in order to give off fertile seeds, and perhaps this is what Luke’s sharp critique of the Jedi legacy has accomplished with Rey. The Jedi texts, if not the Jedi traditions, have been preserved. The past has not been forgotten, but its failures can teach us important lessons."