Well, you’d lose support for devices which can’t handle software DRM playback, old YouTube clients installed on things like TVs which no longer get updated, if you want to support things that only get Widevine L3 support (most devices) you’re not really going to move the needle since Widevine L3 had been broken since like forever, etc.
The main thing YouTube would gain in practice from such a move would be to get DMCA as a legal tool to crack down on people ripping YouTube videos, but that’d require some very significant resources invested into driving Legal processes against average consumers ripping videos, and the return on investment for that is almost certainly abysmal.
Well, you’d lose support for devices which can’t handle software DRM playback, old YouTube clients installed on things like TVs which no longer get updated, if you want to support things that only get Widevine L3 support (most devices) you’re not really going to move the needle since Widevine L3 had been broken since like forever, etc.
The main thing YouTube would gain in practice from such a move would be to get DMCA as a legal tool to crack down on people ripping YouTube videos, but that’d require some very significant resources invested into driving Legal processes against average consumers ripping videos, and the return on investment for that is almost certainly abysmal.