You can live without whatever you ordered for a few days. Be patient while the thing you bought is sent to you for free.
People expect too much. I'd say a few days for an order is pretty acceptable. You have to consider the amount of orders they get, not to mention a lot of them are stuff that comes straight from China. Not everything is actually stocked in their warehouse.
To be fair to the OP, the issue isn't what's "acceptable" or even "reasonable" in the broader sense. Amazon markets (and charges a non-trivial fee for) Prime membership on the basis of clearly defined benefits, so if they're not in fact providing those benefits, they're falling down on the job, and if they in fact "can't", they shouldn't offer it at all, or should change the terms (and/or charge less for it)
On the other hand, they don't claim that everything they offer, even if it's "sold and shipped", or "fulfilled", by Amazon, can and will be delivered within 2 days. As to what percentage of their products are eligible for it, and whether that number has dropped "statistically significantly", I have no idea, and that's the real question - not whether any specific product is or isn't in fact eligible. Could be the OP is just "doing it wrong" by ordering the wrong stuff.
IIt literally is processed, set up ready to go but they sit on it.
Their non-Prime shipping is certainly slower than it was some years ago, but how do you know
that? I don't recall any order status flag that says "it's now been packed and is sitting in the box, just waiting to be labeled and handed off to a shipper.