Actually, SFO just recently finished upgrading their longest runways and associated taxiways (Runway 28 Right/10 Left west-east and Runway 1 Right/19 Left) so it could handle the wider stance and weight of the A380.
But the problem is the length (plus the separation, in the case of IFR). There was a grand plan to use landfill to both extend the runways and increase separation. It was shot down by the watermelons (green on the outside, red on the inside). You'll see ... when the time comes for routing, very few if any 380s will actually touch SFO ...