That's literally the point of the article - the design was changed in a significant way to incorporate a fix to reduce dust, which is spelled out in the patent.
EDIT: Below is wrong, but keeping it for posterity:
Note that the desktop Magic Keyboards that employ the butterfly mechanism do not seem to have the same key sticking issues as those on MacBooks, so it's likely they felt the fundamental design of the mechanism was fine but that it did need an additional silicone barrier for the lower-travel MacBook variant.