That's definitely true. The question to ask (and I mean quantitatively, not rhetorically -- economists can gather data on this) is whether paying a Realtor 6% n

That's definitely true. The question to ask (and I mean quantitatively, not rhetorically -- economists can gather data on this) is whether paying a Realtor 6% nets you more profit on the sale, e.g. whether a house listed on MLS and marketed well sells for 6% more (or sells significantly faster, such that the cost of capital nets you some gain). I expect that it depends heavily on the local market dynamics.