Perhaps chocks help around this problem a bit.
The purpose of chocks is to prevent the mast from bending in light winds. They allow (some) Genoa halyard tension without bending the mast.
Mechanically the following happens:
By tensioning the Genoa halyard the hounds move slightly forward but more important, they are pulled downward. The hounds can only go down if something gives, in our case the mast gives by bending.
So, the hounds are one fixed point (sort of) the other fixed point is the pivot pin (rules require it). If don’t want the pivot pin holes to move, something else has to be allowed to move, in our case the mast foot (backwards). Hence it would be a bad idea to fix the mast foot to the mast step and also we should be careful with applying halyard tension when the chocks are in.
If you are a cruiser you could fix the mast foot to the mast step I suppose. But then you need to take the pivot pin out. If the mast is fixed by the hounds and by the foot it must be allowed to bend in all other places. But, as a cruiser, I want my mast pin in because in my case it is an extended mast pin that doubles as the anchor roll axle.