The problem with Wilde is not just that he and every character he created always sound like they’re quoting Oscar Wilde, but that after him quotations that didn’t sound at least a little bit like Oscar Wilde were unlikely to be quoted, because they didn’t sound like quotations.
The most bizarre aspect of the ‘quotation’ as we now understand it is that words uttered by King Lear when he’s mad are ascribed to Shakespeare, and that words attributed with some irony to a character in a novel can be ascribed to ‘Mrs Gaskell’. Do quotations inform the mind, improve the morals, develop the style, provide us with an instant dose of culture, remind us of that which is already ‘familiar’, and whatever else we’ve been told they do?