Fitting a new staircase wouldn't be any easier either.
The problem here, is that they made a mistake when measuring and ordering the current staircase. And instead of fixing it, they hoped I wouldn't notice.
Our mistake was to notice after we had moved in.
For example my uncle had a issue with his stairs in his new build, but the developers decided to make it right and he was only told after they had fixed it.
On the other hand his developers/builders failed to insulate the roof and that cost him a fair amount of money down the line.
So I guess we'll have to live with it and perhaps only consider fixing the issue if in the future we decide to re-do the floor.
Another thing that annoys me is that I was hoping to be able to replace the carpet on the stairs with something different, a wooden staircase. this issue might make it much harder as the higher rise in the first step will be even more evident (and dangerous) without carpets.