Yep, Ryanair are leaving the Charlerois and Prestwicks of this world behind and moving more centrally.
Glasgow is hardly LHR or CDG, so they won't move back and any expansion in the west will be from there you'd assume. Also as previously said with the rapid growth of EDI there is no FR monopoly in Scotland at PIK now where people would have travelled from the East Coast all the way to Prestwick for a bargain.