The dynamic lights in older engines like Quake3, Quake2, A5 ,etc, are not done in the same way as in A6. A6 uses standard D3D hardware vertex lights. Older engines used a software method for making dynamic lights, which was basically fake, and also slower than A6 lights, and you couldnt have too many at once.

A lot of poeple complain about the current eight-lights-at-once limit, but in A5 you probably wouldnt want even that many lights, because of slowdown.

Also, Quake 3 uses a different kind of geometry than A5, A6, etc. In fact it does use a kind of higher-order surface, that is tesselated maybe even at runtime, I am not sure. But it is tesselated.