Credit this to Jony Ivy's departure
Seems to have helped Apple listen to customers needs/complaints instead of putting design ahead of them. The iPhone 11 gained a fraction of a mm in thickness to accommodate a battery that puts it at the top of the list of all phones in battery life (per Anandtech's testing) and this new Macbook gained a mm of thickness to accommodate not only a larger battery (at the maximum size the FAA will allow you to fly with) but also a return to the old keyboard and they added back the escape key people had loudly missed.
I like Ivy's designs, but without Jobs around to moderate him he start taking things too far, and Apple's laptops suffered for it over the last few years. Now that Ivy is just an advisor to Apple, he no longer has the power to force compromises to get that extra bit of thinness.