The very end: end of the line for his big plans(1940s+)
The Dictionary of American Slang, Fourth Edition by Barbara Ann Kipfer, PhD. and Robert L. Chapman, Ph.D. Copyright (C) 2007 by HarperCollins Publishers. Cite This Source
Idioms and Phrases with end of the line
end of the line
Also,end of the road. The conclusion or final outcome. For example, The editorial pointed out that it was the end of the line for the President; he'd never be reelected, or It was obviously the end of the road for this television series. This idiom alludes to the point where a road or line stops.
[ c. 1900