The correct answer to this open question is the following.
Unfortunately, you did not attach the text, the name of the text, or a link to it. Without the text, we can not cite evidence of it.
But what we can do in order to help you is to comment in the following general terms.
Yes, the United States has changed a lot in some ways over time; however, in others, change has been slow, very slow. As it is the case of racism.
How did America’s treatment of African Americans change through history, and how has it changed since this speech was delivered in 1963?
Without a doubt, the work and the fight for civil rights of Reverend Dr. Martin Luther King Jr had a deep impact on some portions of the American Society and his legacy has been followed by many activists.
There are places in the United States where whites, African Americans, and other minorities groups live in perfect harmony. Unfortunately, that is not teh case in other parts, as we witnessed in many terrible events during the year 2020.
Martin Luther King, Jr. basically demanded in his speech equity and justice for African Americans. That was the powerful intention of the "I Have a Dream Speech," delivered by King during the March on Washington in 1963.