I don't think you understand what is being said about DRM. You are only considering one subset of the entire spectrum of possibilities. It's not that some channels are streamed freely or the DRM itself, it's that there is a DRM scheme that must be considered in order to access channels from the Prime, regardless of which ones they are. Even the copy freely have a broadcast flag, even if imposes no restrictions. Elgato would need to ensure they can properly operate with the flags as well as satisfy the content owners / providers that their solution will honor *all* the restrictions; which necessitates having the proper protections in place. Windows provides, as part of the OS, the proper controls to enface the DRM and as such manufacturers can use that to build products that stream TV channels.
OSX does not do this so it's unlikely Elgato would even try due to the costs of compliance and certification.
So, while it may be technically feasible it's not economically feasible given the low demand for such a product.
I hate to call people out on things, but you are incorrect as to where the copy-compliance happens with this product.
Right now Elgato/EyeTV could, without any help from Apple, allow for users to tune to and record channels from the HDhomerun Prime. But ANY channel that is marked Copy-Once will not be streamed from the HDHomeRun Prime, except to devices that have support for the CCI flags.
More Details:
The DRM/copy protect compliance checks take place within the HDHomeRunPRIME; it communicates with computer to see what OS it has and what it is allowed to stream to it.
I have a Prime and it works like this:
Once Prime is connected and paired with cable company, I can go to the Primes webpage, and check to see tuner status from ANY computer on the network.
I can connect to the prime and configure WMC to connect to the Prime; during this process the computer and prime figure out what can be streamed to the computer. I am now able to watch any program that my CAM card allows me (Conditional Access Module, or CableCard) to tune to; this is based on my cable subscription; if I don't pay for HBO, I don't get to tune to HBO. WMC will allow me to record ANY channel that is marked copy-freely by the cable company.
Now, on my OS X machines; I can do the following with my Prime.
I can download the HDhomerunconfig_gui app and connect to any of my Primes tuners; and tune to a channel. This small app is not very graceful, but allows for quick viewing via VLC if you know what QAM channel your programs are on. If a channel is marked as copy-freely I can open VLC on OSX and watch it. If a channel is marked as copy-once, VLC will not display a stream, as the HDHOMERUN PRIME pretty much says 'NOPE, No can do.' This works for both Clear-QAM and encrypted QAM channels.
This is the crux of the issue; CableLabs would never have certified the Prime if this violated the Copy Protect protocols. I'll say it again, and also a few more times, the PRIME handles the decryption and initial Copy-Protect enforcement.
Likewise, with MythTV I can watch and record anything that is marked Copy-Freely on ANY platform, OS X, Linux, Windows. The only thing that is restricted is the Copy-Once channels. This works for both Clear-QAM and encrypted QAM channels.
You did note that there are TWO systems working here. Encrypted QAM channels require a Cable Card (CAM) to decrypt them; which is what the Prime does. Copy Control Flags (CCI Flags) are flags set by the cable companies on each channel, this is where the computers OS comes into play; as only Microsoft has worked out, licensed and integrated the CCI tech into their platform.
When I try and use EyeTV to control the Prime I can tune to and view any Clear-QAM channels; anything that is Encrypted QAM is not viewable; regardless of the CCI flag. Elgato has chosen NOT to support ANY of the Prime's decryption functionality. I seriously doubt that this is a legal issue with encryption/decryption. I say this because SiliconDust provides the no-frills front end, that will stream any channel to a OS X computer that is marked Copy-Freely.
Again, in summary the PRIME handles all of the compliance issues; if the computer requesting the stream supports CCI flags, then all channels subscribed to are streamable. If the computer requesting the stream does not support CCI flags, then only subscribed channels that are marked copy-freely are streamable. THIS IS REGARDLESS OF CLEAR-QAM or ENCRYPTED QAM.
Again, if I can view the channel through the SiliconDust App, I can view it from any machine, Elgato has simply CHOSEN not to support this tuner at this time.