That would be my worry in any breed. That's why I have always waited till I have a few people wanting pups before I mate my bitches. That was my last litter anyway. She's not having any more after that Caesar and I only have a dog other than my two older bitches.
I have people queing up for a pup from my JR and she needs to have a litter of 25 to fill the orders BUT apart from the unsuitable people many of the other tend to melt away like summer snow and you end up with one or two. I am too old to take on more dogs - by the time they reach maturity..........
Absolutely right - so many times you get folk who think the breed is wonderful and intend doing all sorts of things - obedience, agility, gunwork, field trialling, showing, falconry - I suss them all out first and when I want a puppy myself I let them know there will be a litter available soon. I usually end up with 5 or 6 definites, then go ahead after that and keep in touch with them all through the pregnancy so they get involved. Two of mine have just gone - one couple were to stay overnight last night, got stuck in the snow, car broke down, they had to find a bed for the night half way up the road, got car fixed this morning and got here, headed back down south knowing they could have a long and arduous journey, the other one that went today was much the same just a bit nearer. The third and fourth are taking the train up on Saturday! Get them committed. Mind you I have quite a specialist breed.