Automatic reflow of icons in Finder while resizing window?
If you change your "arrange by" options via "right click" > "arrange by" to any other than "none" spaces between the icons is clinched/stretched according to window size, or icons even get rearranged to the next line if space gets to narrow.

This should be default behaviour without "arrange by" since it kind of breaks list view if active. Sadly Apple rarely listens to customer needs, since they "know what the customer wants".