I don't think you understand? The "server like mmo did back in the day" is the system we indie developers don't have the resources to build. Itch.io already has most of the parts of this system, but the game pages can't be organized appropriately to sell.
If DLC didn't look like a pile of "games" on our creators page, I could probably create a library to ask itch's API about receipts and things would be fine.
I won't say it's an easy change for them (because I don't know), but there's not too much missing. This seems actively neglected and I at least wanna know why.