I'm not in the job hunt market (and have never actually been), as I have my own small business, but if I ever grow to a decent size I am resolved never to treat job prospects like a commodity. Each application is a possible future vendor, a future subcontractor, a future employee. Even if they become your competitor, just having a cordial relationship in place can be used as leverage against them later (treat with grace when declining them, you have leverage to woo them over later to your company). I regularly get resumes in my e-mail every week or so, and while I can't hire anyone on right now, I always give them a personalized reply and steer them toward any leads I have.

There's a definition and a purpose to the word "professionalism" and it's kind of a two-way street. It's clear that today's HR departments are acting with exceptional unprofessionalism, naming efficiency as the driving factor. Back in the 1980s, rejection letters were the norm, and it's interesting (and telling) that even this simple courtesy has been thrown out along the wayside. The things I hear about the hoops necessary to get the application through (such as copying stuff over to the company's forms) is unbelievable, lazy, and really shitty, and not any measure of the candidate's strength. Desperation to get the job and making them put effort into the application is an awful litmus test and is not in any way a good predictor of whether they'll bring value to the company.

I think the companies that succeed in the 2020s will be those that throw HR out on their asses and decentralize some of the job hiring work to junior technicians and a small administrative staff, outsource payroll, and leave employee-employer relations to a small, capable legal team. The rest will just drown in overhead and employee turnover until a leaner company acquires them.