Resizing Artboard with the whole content in Illustrator

Just throw a box over everything - there's a script by Sergey Anosov - https://sites.google.com/site/dtpscripting - that will do that for you, enlarge as required, then make the box your artboard size - you can add a keyboard shortcut to Fit To Selected Art. Add a short cut to the script too...

Yes, you can resize all artboard at once, please check this out:
https://www.youtube.com/watch?v=NoPungS8KXI

Hi there,

Thanks for reaching out. As of now, this feature is not available in Illustrator as mentioned by Jeff as well, however, we have this available in InDesign: New and enhanced features | Latest release of InDesign.Please do make a suggestion on Illustrator UserVoice page as Jeff suggested.

This is the best way of communicating with the Engineering and Product Management teams regarding issues and suggestions so they can be implemented in future releases.

Till the time it not added to Illustrator, you can try Adjust layout feature in InDesign if your artwork doesn't include a lot of drawings.

Regards,

Srishti