I'm not saying that they're not "getting" it. If it takes them three times as long to do each problem as you, they're not necessarily spending a rediculous amount of time "staring at the problem." Maybe it just takes them longer.
That's my point though. I *never* finished my homework in that course. I did as much as it took for me to "get it", and then I moved on. I did exceptionally well on the tests and participated in class a lot.
The lesson that I learned in that course (and the one that I was trying to convey) was that when you're not getting rewarded for doing the work, you shouldn't make it a priority. Understand enough of it to succeed and then move on.
Now, that doesn't work in a class where 30% of the final grade is homework of course. Just hope to god you don't have 4 classes that weight homework that much and pile it on.