And go where? Some still have their family homes, but most do not. Most of us would have no way of travelling through muggle means as Glenda did. So, we can't leave the country, since we're not allowed into any of them. And what about those who come after us? Or the muggleborns that have been born and will continue to be born?
We will never be a society if we all just leave to fend for ourselves as best we can.
As for the curse, the creation of new spells is not a cut and dried process. Was it researching 'weird reproductive spells' that caused the curse? Or was it the method used to bind them? Was it even reproductive spells and not some sort of persuasion spell? Or the combination of the two? Was it the magic itself or the addition of muggle science? In the future, if a desperate couple having trouble conceiving were to try both accepted magical and muggle methods, would it cause the same reaction? Or, what if other branches of muggle science were merged with other branches of magic? Is it limited to only reproductive needs, or could it possibly be any combination of science and magic?
While it is a far less pressing question than that of the castle, it still bears some looking into, not to replicate what was done, but understand it and prevent it in the future.