The point here is that there is tons of money to be made in manufacturing those chips that Intel lost out on by ignoring mobile. That “Apple makes their own chips” does not alone mean Intel could not have profited from this — as indeed TSMC, ASML, and ARM are.
This analysis misses kinda a major point. The nice thing about making mobile SOCs is that the yields are more forgiving. If you have 1000mm^2 of silicon that you're slicing into 10mm^2 dies, each defect (of which there will be many on early leading nodes), will only cost you a 10mm^2 chip, instead of a 50mm^2 chip. And because you're making them in volume, you get many many cycles to improve your process before you try to make bigger chips with it, ie: CPUs/GPUs. And because Apple wanted the increased performance/battery life, they reserved capacity from TSMC on these leading nodes in advance, helping to finance their development while providing a garunteed customer that was going to buy in volume. This gave TSMC a huuuge advantage over Intel that materialzied around ~2018.
In any other context, that might be splitting hairs but it’s a meaningful distinction in this conversation.