Intel is fabbing a lot of things that aren't necessarily their "IP", they like to keep their Fabs busy and running at full capacity even the older ones. Arguably Intel is still making the best Fabs out there, their process tends to be the best in even when compared to TSMC/GoFo and IBM and they are very good at optimizing their entire fabrication process (the non-lithography side) so their Fabs just tend outperform the competition.

Tho that said Intel doesn't want to morph into a Fab as a service company, they just don't want to leave money on the table if they can't fill their 14nm and 10nm Fabs with their own IP/silicon they build it for some one else. It's even more so important now since Intel's dies are pretty darn big even as it comes to 14/10nm optimizing processes on smaller dies can be quite valuable to them. And considering they are dropping their "Tick Tock" methodology or at least altering it somewhat their Fabs can outrun their product line which is never good.