[[WMG: The Tony Hawk Pro Skater games take place in a world where the average human is hardier and more athletic than humans in our universe.]]
Hence anybody being able to hop on a board and skate like a pro, and how falling from the top of a building causes no permanent damage except screwing up a combo.

[[WMG: The Tony Hawk Pro Skater universe is a dimension crossroads.]]
Hence the cameo characters. The crossroads has a strong connection to the Marvel universe, explaining why so many games have Marvel characters.

[[WMG: Alternatively, the Tony Hawk games take place IN the Marvel Universe.]]
And Tony Hawk and his fellow pro skaters are a mutants in this universe, with the powers of super-durability and super-athleticism.

[[WMG: Tony Hawk does not actually exist.]]
He's just a mascot created by Activision to sell their skateboarding games. All of his public appearances at sports shows and the like are just part of a massive viral marketing campaign.

* The only thing against this is that, unless he is a Time Lord, Tony Hawk was active for years as a pro skater prior to the series' creation.
[[WMG: Tony Hawk is a Time Lord.]]
'nuff said.