Netflix's argument for the longest time was they didn't want DRM, but they had no choice.
But, now their originals are becoming a larger and larger part of what they provide, they've steadfastly stuck to having DRM on all their content (first and third party). So that prior argument kinda falls flat on its face.
Shipping new player variants is a pain. The kind of pain you read about on thedailywtf.
Once you have streaming working with DRM on all devices you need a %@#$$@#$@ good reason to introduce DRM-free streaming. Netflix wouldn't want to discover that its own content plays with very low quality on, say, Panasonic TVs made between April and August 2016.
Because all devices can play only DRM videos?
Most devices if not all can play not DRM video and probably not including DRM uses less resources so this is not an excuse not to offer the option, (that can be off by default and only power users could enable it).
Is there extra work, yes it is, but you can't be anti DRM but use it because we need to put some work to offer no DRM version of a stream.
I've worked with this. I've dealt with blackbox player blobs with >100 undocumented tuning variables, and with TVs whose manufacturer didn't really know what worked and what broke.
I wouldn't be at all surprised if some TV manufacturer broke some streaming variant (such as high-bitrate unencrypted smoothstreaming), discovered after a few months, and silently fixed it in new models without issuing an update for the old models.
EDIT: I wouldn't assume that TVs are better at playing DRM. Just from my experience, non-DRM works better (less code that might be buggy). What I'm saying is that once Netflix had a few hundred working devices that worked with DRM, avoiding player bugs became a really good reason to stay with DRM.
Adding an option would not affect TVs that use the old players, only TVs that would update the Netflix app would get this DRM free option and users would have to enable it, if it is not working they can disable it and complain.
I understand your point but this is not a good excuse why people on PCs that don't have the right CPU,cables and monitor can't watch 4k videos that they paid for (..because Netflix wants to give you DRM free video but because some old TVs may not work then you can't get it so please watch low quality stream)
But, now their originals are becoming a larger and larger part of what they provide, they've steadfastly stuck to having DRM on all their content (first and third party). So that prior argument kinda falls flat on its face.