The Veyron can put 1001 HP to the ground because it was designed from day 1 to do so. Whereas cars like the Skyline or even the Corvette were designed to put 505 HP on the ground and but they had a lot of potential.
Many factors come into account like tyres, differential, drivetrain etc. etc.
e.g. the Veyron has an AWD with only 2% of the power going to the front wheels and 98% to the rear wheels. This was done to prevent excessive wheelspin and loss of traction. Whereas skyline has a dedicated AWD and the Corvette a traditional RWD layout.
Also do keep in mind that both of them cost approx. 1/5th of the Veyron.
Regarding the stock output of the Veyron, no other car in the world has 4 turbos with intercoolers. That's an achievement alright, but I read somewhere that without that it's output was like any average supercar which are naturally aspirated.
Acc. to me the Veyron would have been a great car had they made it lighter, slightly smaller and with the same acceleration timings even if they had something like 800 HP in it. 1001 HP is no big deal in North America. Many dragsters, monster trucks can have that. What's important is that it should be nimble, have confidence in handling and be good on the track.
Do you think you can take your Veyron for a drift? Lugging that huge mass of a car the wrong way and correcting it?
Compare that to say a 911.