At least where I shop, on a shelf if a product itself is smaller, more rows of them are used to that the space on the shelf is roughly the same, even though each row might not be stocked to the full depth of the shelf.

In most cases at least. Upper/lower rows are generally where you can find smaller/niche products are more random on that front.

Like the article explains, the shelf placement has in most cases been negotiated and/or maximized for profit. The screens will not help: I expect them doing exactly the same: scale products to subtly promote/demote depending on agreements.

They will do this in addition to what is currently being already done, so it's likely a net loss for consumers.