I think the concern is that if you look here: https://github.com/tc39/proposal-private-fields/issues/14 and other places, you'll see this massive push back from the community, yet the proposal is moving forward regardless.
The only instance of something dropped was cancelable observables. AFAIR it was only because some other group at Google opposed it.
Everything else is carried full steam ahead. Enjoy your import() instead of the vastly superior System.loader. Enjoy your hashes as member access specifiers. Dumpster fire. Template literals. BigInts. `new.target`. Dumpster fire. `import.meta`. Dumpster fire