One of the funniest stories I heard was about the first copy of the Intel 14nm design rules Altera got from Intel. They were heavily redacted, which is something I had never seen in the foundry business.
https://semiwiki.com/semiconductor-manufacturers/intel/7912-...
Additionally, a contract fab tries to be flexible, easier to design for. They make their libraries & design rules work well with commercial design software. A private fab on the other hand can boost yield & performance by pushing increasingly complex design rules on the design team, and the design team can use customized or internally developed software to make it all work.
So in short, they had the best fab tech in the business but they weren't used to servicing anyone other than themselves.
(thanks for answer though)
Yes, it make perfect sense to optimise for you own yield and performance until TSMC overtake you and you no longer has the volume advantage. In manufacturing volume is everything.
It is also worth pointing out Altera is actually a Subsidiary of Intel. If that is what they were going through you can imagine about the others.
