There are only two possible stable equilibria: a "low" don't care/generic letters or a "high" care / informative letters. If most applicants write generic letters, there's no point for the company to pay attention to it. If companies don't pay much attention to it, there's no point in wrtiting more than the blandest, lowest effort letter.
Sounds like you're in a field in the "high" equilibrium. Most of the software industry is in the "low" equilibrium.
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Personally I like cover letters (in the "high" equilibrium of course):
- they basically front load a lot of the interviews, with information that come up in the interviews. I'd rather have as much filtering as possible thourgh the cover letter and CV than in interviews, because it is much more costly for both parties to interview.
- people complain that it overlaps with the content of the CV/resume. The question imho is purely one of presentation: do you want to convey information with full sentences and paragraphs or bullet points? Much like I think powerpoint-style bullet point lists are much worse than actual language to convey rich information, I'd rather have actual text than blurbs in the typical resume. Makes it slower to read and thus requite low number of applicants though.
I’ll add that writing a cover letter is articulating why you are applying and interested in a role. It’s a window into a thought process. It shows someone else how you structure your story, your summarizations, etc. Also, easy way to understand verbosity.
I’m not an SWE by trade so don’t have that experience. But it is useful to practice breaking down your thought process into succinct valuable chunks. In a SWE, it might involve explaining an architectural choice or proposing something new. In sales it might be explaining your pitch approach for a prospect.
My background is actuarial. Highly technical. I spent a lot of time writing why I was doing things. Good then to get a glimpse upfront.
Even when I apply for jobs, I do not like when I am not able to write a cover letter. My CV alone is nothing special, and I often feel safer with the extra information the cover lwtter allows me to communicate.
Note that I am not a software engineer, and the jobs I review or apply to are very specific and have a few dozen applications at most. I understand the situation would be different for a generic job posting ("software engineer providing support in various teams") with several 100s applications.