I agree with previous posts that it certainly has led to folks going there and considering his life and his accomplishments in a way they might not had the monument not been built. Has it had massive knock-on effects in terms of improving civil rights or anything of that sort? That would be difficult to prove.
But walking in and reading the various inscriptions and considering the role Lincoln played in uniting the country certainly has a powerful immediate effect on the observer so I would say that it has accomplished its purpose as I understand it.
Excellent point made by pohnpei. The memorial could have been built in any number of ways and accomplished the same thing. The very fact that it exists would prompt most people familiar with Lincoln and his contributions to reflect upon them. It's massiveness will feel inspiring, however, your words about visiting his home are the same feelings my daughter felt when she toured his home last Thanksgiving.
I think that if the purpose was to honor Lincoln and his importance to our country then yes it has accomplished that. I am not aware of any other purpose of the monument other than to honor Lincoln, but I think it has much more meaning than just honoring Lincoln, I think it reminds us of the fight for freedom and equality for all Americans.
I think that this totally depends on a person's perspective. The purpose of the monument is to honor Lincoln and make us think about how great he was and what he accomplished. When I have been there, I have thought about that, but I don't know that it's because of anything intrinsic to the Memorial. I got the same effect when I went to Springfield, IL two summers ago and toured Lincoln's home. So when I was at the Monument, I felt the way I was "supposed to" but I don't think it was because of the architecture of the monument or anything like that.
In my mind, there are a couple of elements in answering the question. I think that the most primary of these is to honor Lincoln. Built in the tradition of the Temple of Zeus, the memorial places primacy on Lincoln and his contributions to the nation. The inscription of the Gettysburg Address as well as the murals present, one of which depicts the freeing of a slave help to bring a sense of honor in their apotheosizing Lincoln. Yet, I would say that the event that really facilitated the Lincoln Memorial accomplishing its purpose would have to be its hosting the 1963 March on Washington. The fact that a monument in the name of a visionary of the nation would be suitable to play host to a movement that sought to reconfigure the vision of America. It is also quite poignant that the Memorial is the setting for Dr. King's "I Have a Dream" speech. There seems to be a comfortable sense of unity that in the shadow of Lincoln, whose words gave America a voice, Dr. King's words helped to give another voice to America. At that moment, I think that the purpose of the Memorial was accomplished. No other site in America could boast both speakers' eloquent visions for America.