You may not be very familiar with Creative Commons licensing. For example, CC BY-SA 4.0 would prohibit YouTube from using DRM:

> No downstream restrictions. You may not offer or impose any additional or different terms or conditions on, or apply any Effective Technological Measures to, the Licensed Material if doing so restricts exercise of the Licensed Rights by any recipient of the Licensed Material.

(https://creativecommons.org/licenses/by-sa/4.0/legalcode.en)

Most of the CC licenses include such language and have since the first versions.