As my name suggests, I don’t understand your home buying system. I’m the US if you make an offer on a house, it is binding. Exchange dates are set firmly. Sometimes a deal falls apart after a survey because negotiations over repairs fail, but that is really the point of no return. If either party tries to back out at the very least you get to keep whatever deposits have been exchanged and you can sue for damages.
The downside of this system is if you buy a house and your home doesn’t sell, you can be stuck paying for two homes. The upside is that home exchanges are firm. There isn’t any doubt. If you think you are moving, you are actually moving.
I guess my question is, why does the system let people back out so easily when prepping for a move requires so much effort and planning?