Pace Layers are an illustration of the pace at which pieces of a system develop and change.
Fashion, commerce, infrastructure, governance, culture, and nature are the layers in order of fastest to slowest to change.
In terms of interaction design work, pace layers illustrate the lifecycle of design in a really interesting way. Fashion, like stylized UI updates, can change frequently with visual trends. Commerce can also change fairly quickly, as growth tends to be a focus. Infrastructure can change decently frequently, these changes may pertain to new updates or changes to devices. Governance has a much slower rate, pertaining more to things like laws and policies surrounding the technology and design space. Culture also changes very slowly, with cultural norms and expectations from users being widespread and ingrained. Nature, of course, changes the slowest, if at all. The cognitive and perceptual principles of design based on human nature would need real evolution to change.
With all of these pieces of interaction design shifting and changing at different paces, the impact pushes designers to change more surface level things frequently, while still maintaining deeper and more solidified principles that do not change frequently.