There are several reasons why they're not common. First of all, chickens are much more efficient egg-producers than turkeys.
Chickens start laying at 19 weeks of age, while turkeys hold off until they're a far more mature 32 weeks old.
Because of their large size, turkeys would require much more nesting room than chickens, which would make commercial coops less cost-efficient.
Finally, and perhaps most importantly, turkeys are far more maternal than chickens. Generations of egg farming have made chicken hens rather nonchalant about their offspring. They lay eggs and show no interest in their outcome. Turkeys, on the other hand, aggressively protect their eggs and prefer to incubate them.