How to change the default swatch library in Illustrator?

You can start your documents with your own template that has your own swatches. The swatches change with the template for print, web, etc. This used to be easier when we just had two templates — cmyk and rgb — and they were easy to find and to edit directly.

A workaround is to save your swatches, then open the new panel and that make that panel Persistent so that is opens every time you launch Illustrator. Close the Swatches panels. Create a new workspace and use it.

all document profiles (what you see when you open up a category like Print/Web/mobile etc) have their own set of swatches. you can create a new one by opening up a new illustrator file from any profile, adjusting the options you want, stripping out/adding swatches/graphic styles/brushes/symbols, changing the artboard size, and saving it to:

(Windows) C:\Users\Username\AppData\Roaming\Adobe\Adobe Illustrator XX Settings\en_Lang\x64\New Document Profiles

then just use that from the New Document window under Profiles.