What to do about gap in bottom of plasterboard wall when fitting floating floor (UK)
If you're putting back the skirting boards, you can get wooden beading/moulding to cover the expansion gap.

Alternatively you could use a thin bead of hidden flexible caulk underneath the skirting board if you don't mind having a gap, as this would stop drafts coming from underneath.

In my (limited) experience this 2 inch gap is normal on both plasterboarded and normal plastered walls. It seems like there's a few advantages - e.g., it avoids damp problems from the floor or spills, and also allows expansion movement.