webkit fallbacks were removed before initial release due to breaking behavior in old iOS browsers. Bought an iPhone and got css feature detection targeting the issue. Now old iOS uses the elliptical border-radius fallback along with pre-chromium Edge. Everyone else on -webkit-clip-path browsers (including iOS 11+) is upgraded to the full support version.

Full feature global user reach is now over 91% - a big jump from the ~70% at initial release!