Something that Steam used to have, and they recently messed up to the detriment of many small indie devs, was a "More Like This" section on each store page.  It listed games that were actually similar to the game being viewed.  It was a great source of traffic for otherwise unknown games.  They recently changed the algorithm to favor more popular and higher selling games.
If Itch provided a feature like this, I think it might help to promote games, and poentially help developers focus their attention here instead of Steam.  

We already have one. Look for the link labeled Related Games in the upper-right corner of each game page.

Also the related games are shown in many more places too, like after downloading free games and you have a section in your library to show related games from the list of things you own/like.

It make take a moment for new games to have their related games list populated though, as the related games aren't calculated in real time.

Ah!  I did not see it.  I guess the big difference is that in this case you have to click on the link, where on Steam it just shows a few games.