Definitely an interesting idea!
Effectively this view you’ve shared is the same as using the Outline in the left hand sidebar just split up into columns. The reason we haven’t done this is that it doesn’t scale down well to mobile / narrow-width devices with horizontal scrolling often being more jarring than functional.
However, I do see your point that having a way to quickly seen the hierarchical journey from grandparent → parent → child cards with related cards would be very helpful. We will see what we can do to improve this. Including backlinked cards within the preview is one of the other improvements worth mentioning, and this could be expanded for other relations.