What do we mean when we say it today?
We say "elbow room" without even realizing we're quoting Shakespeare. This quote is all over the place today. It's been the name of a book by philosopher Daniel Dennet and another by James Alan McPherson. There's even a Schoolhouse Rock song about the Louisiana Purchase and the pioneers called "Elbow Room."
Everybody needs a little elbow room, after all. Even early settlers.