There is a market for small flock shearing, it's just the cost that's the problem, when you start adding it up you end up charging mileage and travel time, set up costs, then cost per sheep, 10 sheep can end up costing £100 upwards depending on where you are very easily and when you consider the cost of getting yourself trained to do it it becomes a bit of a false economy.
I should know, I used to be a shearer till my arms went silly, so I tried exactly that, small flocks, problem is they're so diverse geographically that the costs go through the roof, so unless your local it doesn't make much sense (or insanely rich)
Anyway that's my tuppence worth