The artifacts produced by pure 44.1 kHz convertion are aliased back down to lower frequencies. It's not about a theoretical human ear, it's about the actual physics of AD/DA conversion.
But the energies of the signal present above the Nyquist frequency (22050Hz in this case) are almost always incredibly weak, and double blind testing rarely shows any indication that humans can actually hear the aliasing.
Mixing process often involves hundreds of tracks, and if each introduces aliasing, this can become a problem. Some engineers do swear by "the final mix is 16/44.1 so why mix at a different resolution?" mantra - that's fine too.
Ok dude, you obviously never recorded anything. Twelve mics on a drum kit, 60 tracks of rhythm guitars, several bass guitar layers, vocals, backing vocals, electric organ, percussions, saxophone solo. Do you think recording them at 44.1 somehow creates a shared "cloud-based" aliasing artifact that I store in S3?
Firstly, it's an amazing experience to randomly interact with people like you - I love and use your software. Hats off and thanks for what you offered to the industry!
But secondly, your statement makes even less sense to me: obviously artifacts do add up. Yes, not linearly, like any complex audio in general. But the more tracks with artifacts I have, the more artifacts I have overall. It's not like they cancel each other (outside of normal frequency cancellation).