Lack of short term IR

There is no such thing as short and/or long term IR! There is just the IR list and you can't be activated until you've been on it for 4 weeks. That's it. How is it that a 2nd person got this wrong?
I understand the rule change but it’s essentially short term IR. I also understand that there’s a cap on players that can be brought back but I don’t see how we’ve allotted those spots already. I just can’t understand how it isn’t being utilized to at least some point (Penning is one). Are we really that bad at evaluating injuries that we’re holding roster spots for players that will continue to sit and take up valuable spots? Or are we at the point where there’s more players than I’ve realized that may be designated for return. I also understand that you need to keep a couple spots in your pocket and can’t spend all the house money right away.