My experience of late is that in my doctoral classes, there is always one or two students who do not deliver quality intermediate products on time if at all, seem to be quite busy with their lives and so are not at all lazy, and then deliver at best fair work (C at best) at the end of the semester. There are exceptions, but none I can think of just now. In these same classes, there are students who do all the intermediate stuff, on time, and then produce first rate work at the end of the semester, and the rest do good work.

Of course, you can make that C paper good if you are allowed to revise it after the semester is over. Not part of the deal in general. You could blame your professor for not warning you, but this is not a good strategy in life when the rules are clear. More likely, the professor assumes you are doing your best and you really are a fair student. If you need to be kicked in the pants to do work, you would do better on a football team with a screaming coach.

You may decide to punt (to use the MIT term) one of your classes, and I guess that is up to you. But your bosses and teachers will have an enduring impression of you that won't serve your interests. When and if you come up for promotion or tenure, you are likely not to have done what you ought to have during your probationary period, and your work just in time (if you do it) may not be able to save you. Actually, you are not likely to have done the work you ought to have done, and then ask for another year. Don't be surprised if the provost says No. Again, there are others in your cohort who have done spectacular work during their probationary period, and they majorize you by a mile.