I don't know much about figs, but are they different varieties? Perhaps that may explain the difference in behavior?? I have a brown turkey that looks great and has loads of figs...and what I think is a black mission that is just as big and has never produced a single fig...go figure!

Among the reasons for turning purple and small size, I can think of two at this time. Check if the tree is rootbound in the large pot and/or the tree got stressed sometimes in the growing season because of heat and lack of moisture in the pot soil for some period (assuming it is a common fig).

Good luck with your trees.