[Firehouse]

Your question is: What is the rationale behind chapters owning houses? Why not have the national office own all of them and use that economy of scale in terms of financing and management?
Remember the old joke: If you're going into a dangerous city to drink all night and raise hell, what kind of car is best to drive? Answer: a rented car.
Nationals found out the hard way that chapters that own their own houses behave very differently than chapters that 'rent' from national. If the chapter is surrounded by alumni whose names are on the loan at the local bank, they benefit from association with those adults who have invested in the house. If you're renting a house in which you have no equity, there's a different attitude toward the structure.
The role that nationals play now is to recruit and train alumni house corp volunteers, to direct capital campaigns, and to offer the best legal and professional real estate advice to their chapters. They also try to stay ahead of campus trends and watch out for problems. And, the nationals do make real estate loans to qualifying chapters. But unless a national is heavily endowed and can afford to lose money on bad investments, assisting the local chapter and making them responsible for their own housing is the safest way to go.