Yes, the submission site talks about removal, and how it takes until the next major release of the browser for the changes to appear in the codebase, and every user will have to upgrade to pick up the changes.
If it were a HSTS preload registry service and API, that'd be different, but it's not.
[b] Is the only way to obtain the full preload list to extract it out of Chromium or Firefox source code? [1][2]
[1] https://chromium.googlesource.com/chromium/src/+/master/net/...
[2] https://dxr.mozilla.org/comm-central/source/mozilla/security...