Is that because older people willingly changed their views, or older people died and younger people replaced them? I suspect 90% of that change is from generational shifts, not people learning with time. In other words, the old died out and the young replaced them.
In my anecdotal experience, most older people I know aren't any less racist/prejudiced than they used to be - they're just afraid to talk about it more.
I find the notion that old people are all stupid, racist bastards very insulting, even though I am under 30. Older people tend to be happier, kinder and have more perspective. Imagine how much more wisdom, knowledge and skill people could accumulate if they did not die so young. If they lived, what would Arthur C. Clarke, John von Neumann and Ludwig van Beethoven be up to today?
It is true young people in our world are often more radical. For better and worse. And for every good change there are other examples where young people changed the world for the worse. The nazis and communists were quite young when they rose to power.
Moreover, I can only reiterate. A fixed world assumption is not valid here. A world with little or no aging will be vastly different.
Think about how much people will change, how many lives they will live over 300 years.
Also keep in mind a society that is able to develop and sustain anti-aging medicine has to be by definition more advanced than ours.
Boredom is not valid, since nobody talks about people being forced to live. However, I don't think I would be ever bored. There is so much to do. So much space so many things and so many minds to explore. The tragedy, the insult of the brevity of life outweighs the dangers of boredom infinitely.