My question is essentially the same as this question:
But I am concerned about "List" view, not "Columns" view.
Is this customization possible in El Capitan? It is a nuisance to be required to manually extend the Name column width each and every time I open a given folder.
I have tried holding down the option key while adjusting the Name column, but when I re-open the folder, the default Name column width has returned.
The root of Finder's peculiar behavior is explained here:
Finders tries to expand List View to occupy full window width. The "Name" column is flexible so it stretches as needed. That is why Finder does not try to remember its width. It just occupies remaining space.
In other words, Finder will under no circumstance open a window with a scrollable horizontal bar; Finder will shorten the Name column—and exclusively the Name column—as necessary to ensure that all selected columns fit to the window.
A sub-par workaround exists:
Remove all of the columns in "List" view except for the Name column (such as the Date Modified, Date Created, Size, and Kind columns) by right-clicking on any given column title and then left-clicking on the titles that feature a checkmark.
Once you only have the Name column remaining, close and re-open the window.
You will notice that the Name column has now expanded to fill the length of the Finder window.
But, two downsides exist for this workaround:
If your filenames are lengthy (as are mine), they will still be truncated to ensure that the window does not have a scrollable horizontal bar. This means that you have to double-click the Name divider anyway if you want to view the truncated material.
And, of course, if you want to view any file's metadata at a glance, you would have to either "Get Info" or re-add the columns to the Finder window.
Ideally, I would like every folder's Name column to automatically adjust to accommodate the longest filename in that folder, so that no filename is cut off or abbreviated. I've created a separate question to address this desire.
However, I understand that this particular functionality is wishful thinking. I would be happy to simply set the default width of the Name column manually one time per folder, and have that position recalled indefinitely.