Sometimes they do if they're woven into a national narrative, like Frederick Banting (the first doctor to treat diabetes with insulin) is in Canada, Louis Pasteur in France, or Nicola Tesla in Serbia AND Croatia (he was ethnically Serb, but born in Croatia, so there's another thing they like to fight over). Tesla's also a good example of scientists who become historical faces for various scientific advances, same as Newton, Einstein, Bohr & Rutherford, Watson & Crick, etc.
Also the history of scientific research is a lot longer than the history of film, so the threshold for memorial is somewhat higher. Actors on the other hand have only really been famous for about 200 or so years, and think of how quickly memory of lesser ones disappear a generation or two after their era. I mean, how many silent film stars could you name? A few, sure, but not that many.
On balance, I think if you sat down and started writing a list of all the famous actors you could think of versus the famous scientists you could recall, actors would probably be a longer list because most of us consume more casual entertainment than we do scientific history, but the list of scientists would still be pretty long as well.
One thing both fields suffer from though is that there's always folks who did a lot of work who get little credit because they're not the star or the face of the project.