As mentioned in the blogpost, they use code splitting and bundle hashing to actually maximize usage of browser cache.

If you have code splitting many chunks will remain the same.

There's a bunch of ways FB mitigates this.

Thanks siblings, for letting me know about FB’s use of code splitting and how it helps caching.

I would bet that js bundling and splitting might prevent that from being true?

Perhaps but thankfully not all webapps are like Facebook.