Actually, it hasn't at all. It's incredibly dull and dated stuff. All sound and fury, signifying nothing.
Truth is, Dave Grohl was a much more talented singer and musician than Cobain ever was (and I think Cobain knew it).
Of all the frivolous, self-absorbed 90's alt-rockers, I think Smashing Pumpkins and Soundgarden have held up the best.
Fixed it. I like Nirvana, and nothing against Soundgarden, but the Pumpkins rule.