Exactly. Having worked for a UPS owned company which dealt with smaller (local retail) delivery and vehicle routing, I have a good understanding of what's up there.
Just because there's a UPS location near you, doesn't mean that your package will ever even go there. It depends on how many OTHER packages need to go to that location and if it's worth sending such a small load to that spot, or to just pack it along to another further away destination knowing that there's another truck waiting to take your package somewhere else.
They're doing what makes sense for them economically. Carrying a package around just to delay you makes no sense and costs them money. Getting your package to you faster (so long as it makes $$ sense to do so), makes them MORE money. Each time a loader has to "handle your package", it costs $$. Lots of $$ considering it's a union job who's "negotiated" the difficult task of moving a box from inside a truck to a conveyor belt to be worth more than a teacher's salary.