Why does Hot Shotting exist?

So I've been reading a ton for the past few months about how to Hot Shot, what to do and not to do, what type of truck/trailer etc. but I feel I'm missing something still. I want to understand why the Hot Shot industry continues to exist today. It is my understanding that Hot Shotting originated in the oil industry and when fields needed an emergency part, trucks would sit at the shop waiting to rush the part out with a non-stop drive as soon as it was ready. Well from what I understand the business is quite different today.

What I do not understand is how the industry continues to exist today.
Has it transformed into doing the same thing that the big trucks do, but just on a smaller scale? If so, why would a business want to pay to only have a small amount of their product moved vs filling an entire semi? Of course there's times when you don't have a full load, but I can't imagine that it happens often enough to sustain an entire industry.

Does it exist as an expedited package delivery service? If so, why hasn't UPS or FedEx come in and just dominated the industry with their size and know how?

What I want to know from those of you who are already up and running is; who are these customers who pay to have stuff delivered via Hot Shot trucking? What are they shipping? What does your load consist of? How often is it time sensitive compared to just being LTL?

I'm sure if I had access to some load boards and could browse around I would see the answer for myself, but I don't want to waste my free trial until I'm ready to run.

 

All great responses so far and does help me.

And in response to you Vilhiem, there may not need to be a logical reason behind it but the way my brain works is I'm an over thinker and need to know every little detail so I'm going to search anyways

As far as most of the responses, that's what I figured - there are some cases where it's cheaper to pay top dollar to have a part special delivered than it is to let your operation be down. I guess my concern is, how often does that really happen and can that model really support all the people trying to make a buck off this industry... more specifically, can it support one more if I join in

 

Something easy and basic that I would love to hear from you guys who do this type of hauling is - what did you haul today and how far? Bonus points if you have a picture of your load!

Maybe I should start a new thread where people just post pictures of their load, what it is, and how far they hauled it?