Physics Has Changed
Ok, physics hasn’t changed (with the exception of exciting new discoveries of course).
But the way we teach and present physics to students has changed.
21 pages into the 1937 book An Outline of First Year College Physics (by Dr. Clarence Bennett):
Most modern textbooks that I am familiar with would take 5-6 times as many pages to reach the same point. One that I just pulled off of my shelf takes over 10 times as many pages.
An Outline of First Year College Physics is available on the Internet Archive: https://archive.org/details/outlineoffirstye00benn.