
I think the size of the stud free in the breed makes a difference, as you say for £200 your putting in a lot of time and trouble.
In breeds where stud fees are the price of a puppy then a large stud fee for no pups is a bitter pill to swallow for the breeder.
It takes 4 pups in my breed to cover foreseeable expenses and stud fee, (price of a puppy), and the average litter is 6 (in 21 litters I have averaged just under 6 pups reared), so if keeping a pup the breeder stands to be in same financial position as stud owner, but with potentially more responsibilities and more work.