If LH wants to establish an ex-LHR long-haul network this will not happen overnight. The ex-LHR market is a mature market with some very strong and well-established players. It takes a long time to launch new routes and build up a presence.
I think the impact on VS is much greater than BA. VS is now effectively isolated. The public statement by VS offering a deal with LH was odd - very unusual for a company to make an approach in such a public manner instead of behind closed doors.