It's probably more accurate to say that the intended audience for the entry level iPads (eg: children, schools) do not need stage manager for the work that they do. I doubt anyone getting an iPad for more professional work would be settling for the base model anyways (I know I wouldn't).To me the lack of M1/M2 chip set makes this product a no go since their are features like stage manger where the M series chips are required to function. If the final product does not contain an M series chip I suspect Apple is doing this intentionally to drive up the sales of higher end tablets that have the M1/M2 chipsets.
It's basically effective market segmentation at work.