> and is hardly ever attacked my entrepreneurs

> but literally you never hear about a real estate start up

I don't think you're looking hard enough: Zillow, Trulia, 42Floors, Yahoo Real Estate, Redfin, Movoto

I'm sure there are many more.

Realty has poor technology because realtors generally don't utilize technology well. The MLS is a festering mess of non-normalized data, and no one cares because real estate is still very much people-driven.