This play is, essentially, about a working class family trying to survive in a world where the odds seem stacked against them and where each of them have their own dreams that they are trying to fulfill. This is something that is universal, and perhaps even more relevant in a world where all humans are experiencing a global slump and finding it more difficult to make ends meet. Therefore it is perfectly possible to argue that this element of the play makes it just as relevant to today's world as it was when it first came out.
The one area that it is possible to argue does not have the same relevance is the theme of race, which has moved on a bit over the last forty years. Black African American identity has moved on from the debate about assimilation that is so focused on in the play. At the time of writing the play, there was a huge debate about Black African American identity that was split between people such as George Murchison, who believed the way to get ahead was to adopt white identity and people like Asagai, who believed that Black Americans had to adopt their original African identity. Note what George Murchison feels about this view:
Let's face it, baby, your heritage is nothing but a bunch of raggedy-assed spirituals and some grass huts!
Clearly this is a debate that has moved on now, and although some would argue racism is still just as acute, in regards to identity it is possible to say that this particular issue that is raised in this play is no longer relevant in the same way.