Let me explain the simple concepts of reality. Scientific research is a service provided by scientists for a fee. That fee is paid for by often times by corporations who use said research to create new products. Those products benefit mankind...
Your other point about how they also create bad products and then market them is irrelevant. We all have our own personal responsibility, you don't have to purchase those products. Furthermore, progress needs failures. Not every invention is going to be a hit, and we learn from those mistakes...
The only factual point you make is "greedy corporations that exploit their work for their own benefit." Yes it's true, corporations don't give a shit about you, they only care about making more money. But in their pursuit of money, they create these great products that significantly improve our standards of living. That is how the free market operates, that is how progress is made. Man didn't invent the wheel to benefit the world, he invented it to benefit himself...
You can imagine all the magical fairy lands where "public banks" come up with money and create inventions despite having zero incentive to actually do so. Who is going to fund this bank? Who decides what products get researched/developed and in what priority? What is stopping you from doing this right now? You do realize this is basically what kickstarter is, but more grounded in reality, right? You can live in fairy tale land all you want, I prefer reality...
But we have gone WAAAY off topic and I do not wish to discuss this further on this topic. You are welcome to make another topic on the positive/negative impact of corporations on American lives. I'd gladly participate and I'm sure there are many here wiser and more qualified than myself to discuss such things...