It isn’t a theory: in the digital world, unless you change the signal, the signal doesn’t change. If the signal is transmitted in a bit perfect way, then nothing has changed.
In other words, the sequence of 1’s and 0’s that make the sound leave your hard drive (yes, even if you’re using a streaming service) and get to your dac as the identical sequence of 1’s and 0’s. Since from the way you’re framing this, I’m uncertain that this is clear to you, that’s what “bit perfect”, or “lossless transmission” means.
Of course it is possible to improve the sound, but you cannot do it in a bit perfect way, precisely because improving the sound means changing the sequence of 1’s and 0’s.
That is why there are different colours in the Roon. One of them says (the purple one) says “lossless”. Another (the blue one) says “enhanced”.
Could Roon release more “enhancements” ? Yes ! Like a GUI for room-correction (or “Dirac integration” if you like brand names). That is something that everyone here agrees on, but that is not what the original claim was.
Can Roon better transmit losslessly ? Nope, because the transmission is already bit-perfect (or lossless).
Can we tell that the transmission is bit-perfect ? Yeap, see my previous posts. I wouldn’t want you to rely on my word for it: try it for yourself. If a DTS file plays back on your receiver, then the transmission is bit perfect.
Here’s where I’m going to really confuse you, but where you might understand what you didn’t before. A manufacturer who claims that the way that Roon transports files degrades the sound also suggests this method.
They also suggest another method: use DoP. Yes, I’ve tried both. You should as well.
The problem myself and others here have is right there: that people are simultaneously claiming that a transmission is bit-perfect, and that they hear differences in said bit-perfect transmission.