VS is focused more on providing benefits to high fare pax and its own elites, as it is not a member of Skyteam, is not concerned with providing EliteAccess-type benefits with CO elites. In other words, VS does not care about offering benefits to CO elites traveling in VS coach because it does not see any benefit to be derived therefrom. But VS is more than happy to accomodate you if you are traveling in PE or UC. Also keep in mind that CO does not offer any reciprocal benefits to VS elites.

And, as CO would prefer to retain paying J pax on CO metal, CO is not interested in forking out a fortune to offer its platinums access to VS Clubhouses. CO partnered with VS because CO pax need mileage-earning flights to LHR and AA was already partnered with BA (and BA is in OneWorld). I'm sure that CO would prefer that paying J pax stay on CO metal.

If you frequently fly VS in coach and fly enough to maintain your CO elite status without including your LHR flights, I would do as others suggest and sign up for VS flying club and begin crediting your flights thereto.