First thing, keep in mind none of this is your fault. With assignments like these, the expectations are very clear, and if the paper isn't turned in the by the time the semester is over, they're grades are whatever they earned. No paper, no marks.

At the same time, I'd like to offer some small criticism. When I work with students, I don't check if they have the basic ideas at a few weeks before the deadline, that's usually supposed to be done a month or two in advance.

This might vary and other profs will do this differently, but I give them time in class to work on it, and I even, with the student's permission, showcase the thesis statement of their essay as an object lesson, especially because a surprising number of undergrads dont write proper thesis statements, and for history papers that is a great way for the paper to start rambling.

Some of you might criticize me for babysitting my students, but I also have them write out an outline, and plan of due dates, and I make them meet me 3 times in the semester to discuss their plan and any possible alterations to it.

To be fair, I do teach freshmen and sophomore level undergrads, but these are just my 2 cents