I've seen Marilyn's movies. As far as beauty goes, I don't see her as better looking than many of her contemporaries like Sophia Loren (who I regard as a better actress as well).
As far as going to the movies to see exceptionally-cute women, there are lots of cute women on TV as well. Much cuter than the average "porn star".
I don t think Marilyn was the most beautiful either. But her career was almost entirely based on her looks. I mentioned Niagara because it is almost soft porn. She is shown in tight dresses, taking a shower, sleeping nude under the sheets, etc. And she wasn’t even the lead (Jean Peters was). She was quite successful for a 10 year stretch based on being a sex symbol.