50 years ago was 1976. Pretty sure there was no particular problem incuding photos or illustrations in paper journalism at that time. Maybe for very low-budget newsletters it would have been.
I think USA Today (1980) was considered repulsive not just because it was colorized and a newspaper but simply because it put more space/resources into illustrations than was considered tasteful. A typical paper would reserve photographers and illustrators for front page and significant stories.
That depends. For the most modern presses (1970s modern) it was no problem but many small newspapers still used the linotype and a press that couldn't handle pictures without much effort.