But Global Foundries doesn't have the ability to do newer/smaller node sizes, so they can't "level up" at a future time. That is, unless Global Foundries makes some massive investments. Which they've not demonstrated any willingness to do, nor competence at doing.
This deal with TSMC at least seems like it provides a way forward with people that know how to execute. One that the Global Foundries option can't credibly provide.