What am I missing?

I've been keeping up with things on here for awhile now. I also am in an area where there is alot of truck traffic. I owned several oilfield specialty service trucks a few years ago so am familiar with dot regs and the such.
I have family that is in the trucking business in La. and several friends too.
My question here is if the business is as bad as I hear form everyone how is it possible that there are so many trucks on the road? If it is THAT bad then how do you afford to keep going? It would seem that at some point in time you would simply run out of money and be forced to quit. Maybe the people I see living under the under passes here were truckers that just didn't get it? I have noticed that thr trucks running the containers from the port of houston to the rail yards are total junk. I can't believe they are alowed on the road at all. Go to the interstate just outside of the city and it's a whole different story, nice equipment for the most part. get out on the interstate and still again better stuff. I have discussed this with the family in law truckers and they say they are doin good...not as good as a few years ago but still not bad. What do you attribute to the struggling trucker? Underfunding? Seems like the ones having the hardest time are the people who start on a shoestring with little or no reserves, little or no business background, questionable equipment , lots of overhead ..etc. Or to sum it up just a bad deal waiting to get worse in a hurry. Do you think this is the case or am I way off base. Is it that bad or just in some peoples opinions?