What’s really fucking annoying is that my ‘Devils Advocate’ Star Trek brain started putting together how that might work.
We know that subspace distortions impact quite a lot. We also know that people have memory engrams. So… why not? The ‘argument’ that came out immediately was:
Subspace distortions are fine in small quantities but when you’re being flung across the galaxy, it’s not quite as safe. With those distances, the humanoid brain can’t stand up to those rigors. The Doctor would likely survive, but the distortion would eventually cause a polarity reversal for most organic brains. Instead of saving memory engrams, it starts slowly deleting them. Leading to the unfortunate consequence that by the time they’re in the Alpha Quadrant, even if they could be de-lizarded, they would have no memories of who they were before that.
You know what? Accepted. I accept your explanation.