Big companies USED to own land.... same as Banks and Insurance companies USED to put up headquarters buildings that, sometimes, were architecturally rather good ( for the times). Nowadays no. Scotia Bank for example does not own Scotia Place... IIRC it holds some of the mortgage and certainly leases quite a lot of the building.
But if you, as a company, OWN something then if you go bankrupt, people can take it from you, if you only lease it then your creditors have no action against the landlord and they can go to hell before they get anything of yours.