It seems I do more typing than the good folks at Kinesis expected:
In round numbers, the keyboard is all of two years old and that little ridge is pretty much history.
The ultimate fix will likely involve a dab of epoxy, but a duct tape snippet should show me how much of a bump my fingers need to find the home keys without conscious thought:
Early returns suggest one layer isn’t quite prominent enough; some iteration will be in order.
And, yeah, I should yank the keycaps for some deep cleaning.