I don't know if these instructors have TAs because both classes are online. This is the 4th school I've attended and have had the same experience at all of them. I've had the occasional instructor who was really good about getting things graded and the scores posted, but they are the exception rather than the rule.
As I said previously, I do understand about the workload and the difficulty of keeping up, but that doesn't excuse it. We all have duties we are expected to keep up with. When we don't, there are consequences. There don't seem to be any consequences for college instructors as long as they get the final grades turned in. Sure, I could make comments in my course review, but that's after the fact and I'm betting it has very little impact.
It is very frustrating for me, as an equally-busy person, to put in a lot of effort to write a paper, get it turned in on time, then wait weeks, even months sometimes, to get a grade. Then, at the very end of the course, you get weeks' worth of grades all posted at once and it's painfully obvious the instructor never even read your work, or probably just glanced over it to make sure you didn't make any glaring mistakes. Tell me how that's learning on my part. I could probably write complete nonsense and as long as I turn it in on time and it looks nice, I'd get a good grade on it because the instructor is just too swamped to take any time to actually read it and provide feedback.
My point here is that there should be rules for both sides. If I have to meet deadlines in turning in my work, the instructor should have to meet deadlines in grading it. I think 2-3 weeks after an assignment is submitted is a reasonable amount of time to wait; 4 or more weeks is not. If the instructor cannot adhere to those rules, then he/she should not impose deadlines on the students either. The student should have until the end of the course, or close to it, to submit the work since that's probably when the instructor is going to look at it anyway.