Yes that’s correct. If you were owner operator you might be aligned with a particular firm (their name on your truck) and their dispatch would find you loads or you would also know people. You could have a dry van and look for generic loads but lots of guys I knew had specialised equipment (flatbed, tanker, etc) and over time you locked in good lanes and repeat customers. I met a tanker driver once who started in Florida, took orange juice to Canada, picked up some food ingredient in Canada , drove it to somewhere in Tennessee then took something from there to Florida. And repeat. He did that triangle for 10 years. Shipping used to be a real people business. If you had an unusual or unexpected load you’d call your 5-10 providers and they might have capacity or not, or do you a favour and call their buddies for you or not. That would almost always work out, if it didn’t you’d call the sales person from the new 3pl or trucking company who had been wanting your business and he/she would move mountains to get that chance. Definitely an interesting industry full of problems to solve. Don’t think it’s the same any more.
Love your thinking. Rather than comingle the plastics with waste, let's keep them separate at the landfill for use when future humans figure out what to do with it.
By mixing it all together we just make it much more difficult for ourselves later.