They extract quite different margins from their products; the big markup (and thus profit, and thus the justification for market valuation) happens not when a chip is manufactured but when it's put in an iPhone.

The iPhone's processor manufactured by TSMC contributes only about $40 to the cost of the phone (https://www.phonearena.com/news/iphone-12-bill-of-materials-...).

The Macbook's M1 key advantage to Apple seems to be that it's cheaper than the previously used Intel processors (https://www.techspot.com/news/87663-apple-possibly-saving-bi...), so again, it's a major boost to the profitability (and value) of Apple, and just a minor one to TSMC who gets paid a reasonable but effectively commodity price for their manufacturing.