For one, yes it IS possible to just bury the accelerator when the gust kicks in
The very best guys go 32-35 knots as max straight line speed on the normal big racefoils.
Where "upwind riding" happens around 15-16 knots for these, when going fast, and you can go a bit higher and only around 13 knots for some.
Seeing these guys go from 12-13 knots and to 35 is insane to watch, awesome acceleration
For mere mortals it is different.
When we go 25 knots we feel extremely fast
There are some issues regarding going faster.
For one it would require a different foil, much smaller wings of course.
But the mast is a major problem - as it has to be stiff and support all load, but when you ride with say a feet of the mast underwater, you get a ridiculously amount of "total loss" drag, thus you have to make a much thinner and smaller lower end of the mast - which is not easy
The mast does not have a function besides structural support, thus every part of it submerged is wasted drag
You cant go fast with your normal hydrofoil, too high drag so not possible to get sufficient pull to go several levels up in speed IMO.
As I assume we are talking 50knots+ here if records ?
The other problem is cavitation of course.