Considering the M3 was built on an earlier, more complex 3nm node (3NB), I wouldn't be surprised if the M4 was cheaper to produce from day one.
It would really surprise me! Proposed tariffs on semiconductor imports, including those from Taiwan, are poised to impact TSMC (Taiwan Semiconductor Manufacturing Company). The tariffs, ranging from 25% to potentially 100%, aim to encourage domestic chip production in the U.S. And you know who fabricates Apple's chips? All of them? That's right, TSMC! In response, TSMC has announced another $100 bilion investment to build out capacity here in America, on top of the $60 billion already allocated. But what good will that do in the short term? Can't build and staff those facilities overnight, it's a multi-year project. And once they're up and running, they'll have to face the higher wages Americans need to live here, which will increase their costs. And of course, they have suppliers in Taiwan, too, so they'll have to pay import tariffs on those items.
And that's not even factoring in the CHIPS Act. The CHIPS and Science Act, signed into law by President Biden on August 9, 2022, is a $280 billion legislative package designed to boost U.S. semiconductor manufacturing, research, and development. President Trump has indicated he will repeal it. What effect that will have on chip manufacturing remains to be seen. Not if it will be bad (we know it will be bad), just how bad it will be!!
So maybe ON day one, but not for long. Your next laptop is going to cost more. Bank on it.