It is possible that for the young and people of modern times, watching old films can be quite boring. But the old persons and middle aged, I am sure they would prefer the old films.
For the youth of today, the faces, the dressing sense, and the dialog delivery of the yester years can be boring. The culture and traditions, sensitivity in family relations, sacrificing nature of heroes and heroines are not so attractive for the new generation. It seems that the story runs slow and the people speak very slowly and too softly. Probably the kind of crying scenes bring headaches to the children. The stories in old films represented the state of people decades ago. Those stories could appear to be irrelevant and boring.
Due to the invasion of foreign culture and movies, the youth is impressed by a different set of values, incidents, dialogues and behaviour of actors on the screen. Old movies gave more importance to actors (& people) above certain age and the new movies give importance to actors (& people) below 25 years.
However, there are many who like the everlasting old comedies, mythological and patriotic films.