It's unclear whether they mean a tape out failed and requires a respin (3 months) or they just decided to wait before trying to tape it out in the first place. Even if Vista isn't out when the G80/R600 are released, DX8+Geforce3 and DX9+R300 were gigantic leaps even aside from the new features, no reason to think DX10 will be any different. Also the R300 was available before DirectX9 and that worked out just fine.