Wahabism and Al Saud were the natives of Najd an area totaly different from Hejaz( where Mecca is) historically, culturally.
The reason why Wahabism become so strong is because they got the area of Hejaz under their control, which is historically evident that who ever has Hejaz under its control rules the Muslim World. Its much like if Spain gets Vatican under its rule it gets in a position of dectating.
So if no Hejaz for the Saudis than no much longer the power they or Wahabism will have.