It's really hard to combat, the thieves are professionals. As an owner of a few high $ bikes myself I encourage all of our site teams to recommend bike owners register at a site like
bikeindex.org/. These sites act to reduce the trafficking of stolen bicycles (as a business) as prospective buyers can run the id number on the bike to check ownership status. Other than that, cameras, secured access and hardened locks on the bikes help but will not stop a cordless grinder and a diamond disc.