I went to an investment club meeting this year and a guy named Rick Harmon seemed like he focused on probate pretty much exclusively. He mentioned that he gets some killer deals, but he also seemed to be very well connected to get them.
He did mention that most people have an aversion to probate becasue they simply do not understand it and while some deals might take longer other are similar to a regular escrow.
I would think that 99% of people avoid the areas they are unfamiliar with, but the people that do the research, embrace it and get familiar are not going to have as much competition for their deals.