Why do some departments not offer master's degrees anymore? I am a bachelor's student currently in my junior year; and I am looking for a graduate program in mathematics, in either UCLA, or UC Berkeley.

However, both websites say they only admit PhD applicants, and no longer master's applications, and this worries me a bit.
Does that only mean that the master's applications are closed as of this year, and that they will open again during fall?

I'm just a bit unfamiliar with the American system!
Funded masters degrees are getting generally phased out in most fields. They seem to be replaced with unfunded masters' degrees, and/or all students are getting funneled into the funded PhD programs.

The prevailing wisdom (as far as I can tell) is that funding masters students is a waste because as soon as you've trained them to know stuff they leave, unlike a PhD student who you can get a few years of useful work out of. Unfunded programs are great for whacking that international student or trust-fund kid money pinata.