We'll be glad to comment on and add to your thoughts on this topic.
I got no idea. Except for maybe because of the rapid increase of blacks within the Harlem area(due to the great migration in which many blacks from the south moved north) and having people with powerful minds like DuBois, Garvey, Hughes and few other appear, people began to look up to Harlem as a place where African-American culture began to develop.
You have a great answer!
The word "Mecca" means a city that is revered and draws believers and pilgrims. Talented performers were drawn to Harlem to pursue their careers -- thus perpetuating Harlem as the center for African-American artists.
Few more questions.
Why did the time period (1920's) allow the Harlem Renaissance?/Why was it a good time for the Renaissance?
How did the writing grow out of Negro Spirituals?
And What is the Spoon River Anthology?
For the 1st one I believe that the return of the black soldiers from WWI enabled the whites to accept them a bit more. With also the rising economy there were more financial opportunities for the blacks.
For the 2nd and 3rd I got no idea.
Your answer is great.
These sites will help you answer the other two questions.