I wonder where does the drop happen in the funnel. Probably the most troublesome part is writing cover letter? I remember that I have to create a template in LaTex for my cover letter which i can just change the company name and responsibilities.
At this point I’m not even sure if big companies read cover letters at all.
That's probably a big one though I'd guess the biggest would be the double data entry, where you're asked to provide a resume (usually in Microsoft Word format) and then enter all of that information again, broken up into dozens and dozens of poorly designed textboxes. It really is a huge middle finger to applicants and makes clear that the company believes your time does not have value.
Conversely, after 27 years as a hiring manager, the vast majority of people I've hired didn't even send one. I think a good cover letter certainly can make a difference, if it helps highlight why you're a good fit for this specific role if it's not obvious from your CV, but I rarely send any myself, and not for any of the jobs I've actually gotten over the years.
As an employer I always read the cover letters. You had better have a slight clue of what job you are applying for or your application ends up in the garbage.
At this point I’m not even sure if big companies read cover letters at all.