Might be wrong here, but isn’t that also a limitation for most component column based ECS implementations? (I mean each entity can have only one instance of each component)
Depends on the ECS, most systems I've worked in will let you do two addComponent calls of the same type and then they'd just get added to the array of components to batch process. This is really common for mesh components (although there's usually mechanisms to specify dependency/ordering to avoid off by one frame issues).
