Fabless companies are often at the mercy of the foundaries, but when you have a customized process, it is very difficult to bring it up in a fab. It can result in many issues that will delay a startup of manufacturing. That is just a fact of life. It is unproductive to point blame at your supplier. You have to own the project and lead the supplier to where you need them.
I am somewhat familiar with what it took to qual the Ramtron units on the 130nm process at TI. TI spent around ten years to doggedly beach that queer Ramtron FRAM whale, and the device process technology is nuanced to put it mildly.
IBM ought to think of simply licensing the TI process technology and get their pain over with quickly. The capacitor stack formation and etch is a technology ballet.