Store brushes inside the psd file like in Illustrator.

Including abr-files in layered psd/psb/tif-files might clash with the file formats’ specifications … not to mention that it might confuse easily confused Photoshop users. 

I also struggle with it, and I believe that addressing these difficulties would lead to significant improvements.

I am not an Adobe employee but to me the request seems rather »far off«. 

Photoshop Brushes are very different from Illustrator Brushes. 

A Brush Stroke in Photoshop creates pixels on a Layer, in a Channel, … not vector content along a Path as in Illustrator. 

But I have also created Brushes for specific jobs and remembering to store the abr-files with the psd/psb-files (for potential future edits) can be a challenge, so I see the potential benefit even if I suspect severe technical problems.