It's very possible the stairs are not currently code compliant (too steep, too high riser, too shallow tread) and they are grandfathered as is. But if you move them you will have to meet current requirements which will take up more space, usually. Most antique houses here leave the original stairs intact even if the house is gutted otherwise, for this reason.

To best advise you, we need a sketch on graph paper of the current downstairs and upstairs layouts, showing the existing and proposed stairs.

We need to see the space your are talikng about or at least some drawings. I do agree moving stairs is expensive and how much space do you really by doing this you need space at the top of the stairs no matter wht side they are on so floors plans please and yes they will need to brought up to code if moved for sure which BTW will probably need more space.