You just have to realize that teaching at many (and all the renowned) places is seen as a necessary evil. No professor ever got tenure because of their teaching skills -- there are incentives only for doing research. So, basically, don't do your undergrad at a research university unless you're looking to get into research early. Small liberal arts colleges (SLACs) is where it's at. They'll make you write a lot more (important) and the faculty is hired primarily to teach.
That said, failure rates in Calculus are going to be high no matter what a professor does. You learn this shit only by doing many, many examples. More than the assigned homework. But in an environment where many students don't even complete their homework, you're just not going to have a whole lot of students who will go beyond that. Some pick it up quickly and they'll pass, but many others won't and have apparently no interest in trying to do what's necessary to understand it. Instead, they'll just tell you how they "can't do math" and somehow still deserve an A 'cause they tried soooooo hard.
You'd be shocked how many students think their grades should be a function of how much time they (claim to have) put in, even if that time somehow wasn't applied to doing the homework. Which is still not as frustrating as students figuring out the morning of the final exam that they didn't get a concept from the beginning of class that was at the heart of the rest of the semester.
So for those getting ready to return to school: if you don't get something after a lecture, go to the next office hours. Don't be afraid of your professors... they'll like you more for showing up not just the day before the exam.