Odds are that most of the traffic Fedex and UPS are getting is from Amazon, and the little guys are getting shut out.
At least where I'm at, almost none of my Amazon orders come through fedex or UPS now - everything is delivered by an Amazon driver. And they have an incredible amount of Amazon vans running around. I went to lunch the other day and counted 3 within a mile of my house.
That does make me wonder how they optimize routes. That and the fact that I had 4 different drivers leave a package at my house the other day.
That only means the 'last mile' (figurative here) is done by Amazon. I believe there may still be third parties in between depending on the item/location.
I can't imagine what they're going through right now.