It has been the general consensus that, since the play's opening day in February 14, 1895 at the Saint James's theater, The Important of Being Earnest is a play whose style, dialogue, content, and use of witticisms is so excellent that it has transcend the changes of time.
This is the case because Wilde is not the typical dramatist that will create a thick plot so that the characters can interact. Instead, he will create deep, quirky, silly, and unique characters that activate the very essence of the times, making them ageless.
The best example is the character of Algernon: A bachelor of aristocratic roots who lives his life in debt, irresponsibly, and irreverently admitting how little he cares.
My dear boy, I love hearing my relations abused. It is the only thing that makes me put up with them at all. Relations are simply a tedious pack of people, who haven't got the remotest knowledge of how to live, nor the smallest instinct about when to die.
He is no different than the modern "trust fund babies" that we see in reality TV shows who live off the names and fortunes of their families and spend their entire time having fun and partying. That is exactly the Algernon that Wilde created more than one hundred years before.
Similarly, the imperious and uber-selfish nature of Lady Bracknell reminds us of the very rich and famous divas of modern society who stop at nothing to belittle, humiliate, and insult those who are not their equals.
I confess I feel somewhat bewildered by what you have just told me. To be born, or at any rate bred, in a hand-bag, whether it had handles or not, seems to me to display a contempt for the ordinary decencies of family life that remind one of the worst excesses of the French Revolution! [...] As for the particular locality in which the hand-bag was found, a cloak-room at a railway station might serve to conceal a social indiscretion–has probably, indeed, been used for that purpose before now–but it could hardly be regarded as an assured basis for a recognized position in good society.
Wilde, who loves to mock aristocrats more than anybody else, would use these qualities and would ridicule them by making them even more pronounced. However, she too has remained relevant: After all, who does not have a family member so annoying, and yet so powerful, that nobody can get rid of them?
Therefore the depth of the characters, the brilliant dialogue and the exchanges and dynamics that occur make the play one of the most relevant of all times and, in my opinion, one of the best in English literature.