Well.. here's the thing..
They standardize on a few sizes of cardboard boxes.
There's higher risk of smaller boxes getting crushed under wheels, falling off sorting bands, getting forgotten under machinery that sorts packages for days or weeks, getting damaged at transport, so it often makes sense to use larger boxes.
They often don't have several types of packaging, so if they only have bubblewrap or air bubbles available and they need to protect a single connector, it takes more time to be careful and cut just a small piece of bubblewrap then use scotch tape to hold the bubblewrap together, compared to just grabbing a handful of protection material.
I can't give you a link right now, but there were some discussion threads regarding shipping small items on other forums and people from Amazon and other companies said extra bubblewrap is less expensive and less toxic to environment than the cost in support calls and returned packages and refund requests due to people not finding small sd cards and other such items in their packages (because they slip between cardboard layers or through open holes when shippers flatten them or throw them around).
There's other reasons as well but I can't remember them right now.
Newark isn't that bad here, I don't see them sending me oversized boxes. They also like to use big bubblewrap envelopes (about A1 sized) for heatshrink tubing, ribbon cables, headers etc small stuff.
Maybe I'm just unlucky, but usually they have everything in stock when I try to order something but then as they start to ship it, some parts show up as available in 3 days, some parts in a week and so on.
So almost every time, I get the order in 2 or 3 separate days, but all within a week usually.