If there's still 1 thing that saves the theory of "Shanks is Roger in current era" then it's their cooperation and relationship with the Government associates.
Roger teamed together with Garp to take down Rocks, and later to leave his unborn son to Garp's care.
Shanks also worked together with Goroseis for still unclear objective, and later will leave his crew in Goverment's care (Impel Down) after Teach took his life.
Roger teamed together with Garp to take down Rocks, and later to leave his unborn son to Garp's care.
Shanks also worked together with Goroseis for still unclear objective, and later will leave his crew in Goverment's care (Impel Down) after Teach took his life.