The reason market challengers outsource to TSMC is because they don't have enough revenue to support their own fab line, with Intel taking majority of the revenue. The precise reason Intel kept their own fab is because it's the makret leader that wants to keep their competitive edge, that is under the assumption their own fab is more advance, and for their use only. However, now that TSMC as a fab somehow got more advanced. It meant Intel's in-house fab has failed in that mission. That doesn't mean Intel's challenger's gonna hand their production to Intel's fab. Intel obviously won't just turn over their technology for their competitors to use either. It's quite impossible and unconventional to do.