This is an interesting POV, which I hadn't considered.
There are more outcomes possible than the one you suggested though. It's possible for one DRM standard to win out over the others, thereby entrenching one single proprietary, closed, intrusive and potentially patented solution into something that just has to be supported.
15 years ago we called this Flash. We've still not gotten entirely rid of it.
Maybe it's prudent to avoid a repetition of that situation.
You should read up an understand the difference between EME and CDMs. You are confusing them. I can't blame you, because the EFF/FSF are often conflating the two.
EME specifies a protocol to establish communication between a webpage and a DRM module. The DRM module is called the CDM (content decryption module). EME is what the W3C was standardizing, and can be implemented in open source.
The CDM is not standardized and is a binary, closed source blob.
In the end that doesn't really matter as the result stays the same. Sure you can openly implement EME but not the CDM, but without the CDM EME is pointless.
There are more outcomes possible than the one you suggested though. It's possible for one DRM standard to win out over the others, thereby entrenching one single proprietary, closed, intrusive and potentially patented solution into something that just has to be supported.
15 years ago we called this Flash. We've still not gotten entirely rid of it.
Maybe it's prudent to avoid a repetition of that situation.