We don't know that. I cannot imagine we have a perfectly accurate mapping of all mDNA neanderthals had. All current mDNA could actually have been neanderthal

We don't know that. I cannot imagine we have a perfectly accurate mapping of all mDNA neanderthals had. All current mDNA could actually have been neanderthal at one point in history. How would we know otherwise? With absolute accuracy? We certainly don't have access to thousands upon thousands of samples. Do we? (I genuinely wonder this now)