So I've got a bit of a selfish reason for making this post aside from starting an autistic debate about the back end of RPGs again. I'm just playing around right now with learning inventory mechanics and learning them.
Every time I look at grid inventories, yes they're sometimes quite nice visually laid out and everything and it lets you sort stuff well as the player when they're coded properly. At the same time though from the player's perspective I have never really cared much about grid vs list I played the hell out of Skyrim and Fallout 4 and I actually quite enjoy the list inventories because you can quickly scroll down clicky click your way through stuff and you're done whereas with grids you're dragging and dropping things constantly and having to split items in a fairly tedious way.
My main point with this ramble is though thinking about inventory design does anybody here actually care that much about what the inventory screen looks like if it's clean and usable? I bring this up because if I choose to code a list over a grid in my projects that have inventory systems it's a remarkable difference in the work load, lists are definitely easier to deal with and take less code compared to complicated grid systems if all you want to do is let people pick up and drop stuff or equip things and there's not much else going on.
For extreme examples, think Skyrim vs Diablo 2 in terms of how they have their inventories. Been fed up of bloated RPG after bloated RPG being released so I'm going to play around with these ideas for the lulz while I think about my other work now my RL garden stuff is calming down.
The only reason list inventories exist in modern games is due to console gamers and controllers. that's it. that's their entire reason for existing.
It's certainly a big part of it, but I wouldn't say it's the only reason. Try managing 120 items in your inventory in an MMO with a grid list and tell me that isn't a pain in the ass.
There certainly is a reason why inventory organizing mods are usually one of the first and most popular things in any MMO.
Better than managing 120 items in a list.