Apple does not nor have they ever made displays. Intel on the other most definitely makes CPUs. That's the difference.
Apple just recently moved back into the hardware space after farming everything out since the iMac gen2 days. Hell, I remember the Mac clones. I miss Power Computing.
I'm not even sure you could say Samsung is a competitor to Apple anymore in the phone space, at least in the US - I doubt there's much switching going on where people are frequently enough making a decision to change ecosystems, at least for existing customers.
Samsung's competition is Huawei, Xiaomi, Oppo, etc.
Apple farms out its displays to Samsung, a competitor. It's just how business is done.