That was always my feeling, there's nothing onscreen to suggest that those the faces of Doctors previous to William Hartnell.
No offense meant, but I think you're being deliberately obtuse. Yes, there is something onscreen that does more than suggest that: we see the face of Tom Baker, then the face of Jon Pertwee, then Patrick Troughton, then William Hartnell, then other guys we've never seen before, while Morbius is saying "how long have you lived?" and "back, back to your beginning!". It's like one of those "complete the series" things in I.Q. tests. We're being very explicitly and very deliberately lead to think that those other faces are previous incarnations of the Doctor.
The only reason why some people claim they can't see it is because they can't see beyond the rationalization that is necessary to make sure that "Morbius" fits into the larger
Doctor Who canvas. Some fans are like dramatic antibodies, desperately trying to fill in anything that looks like a plothole. Me, I don't care about continuity, especially in Doctor Who, and I'm happy to watch this scene for what it is, knowing full well that the series has gone in a different direction since then.