Very few people will put in the effort if there will not be a ROI. If a company isn't going to respond at all, let alone favorably, there are other things they can do with their time beyond toss a customized application into a black hole.

I personally don't use AI for job searching to do more than check the keywords compared to my resume, but I see why people would optimize their time this way.

"But this shows you really want THIS job!"I wrote a cover letter for a company whose products I have used since childhood. I used examples and filled it with reasons why I chose this company, and drew on the "emotional connection".I asked people on various sites, people I've worked for in adjacent indusries, for an "in" to the company to get my application seen, to no avail.It took them 7 months to send an automated message to me on a Sunday that the role has been closed.No interview, no conversation, no job. You tell people to "write a cover letter" and "tailor their resume", you're going to get the same thing over and over again written with AI because they have to send out as many applications as possible.