Is it not the case where you are / in most countries as it is in the US that most homeowners have loans out for most of the value of their property (sometimes even more!)? In which case, surely the value of the current home matters quite a lot?
Maybe you mean to say that what matters is the difference between the price of the desired future home and the amount of salable equity that they have in their current home?
Maybe you mean to say that what matters is the difference between the price of the desired future home and the amount of salable equity that they have in their current home?