Were your applications that good of a fit? You sent 450 applications for one hiring. Very roughly speaking this means you expect the employer to carefully consider 450 applications for their one job opening (assuming roughly speaking, that everyone does the same). "Carefully" is clearly not gonna happen. You sprayed and prayed but the employer is hiring one person for that one position (not quite true) and can't just spray and pray themselves.

You may have indeed found 450 real and fictitious openings that would be a great match for you. Yes, not impossible. Still the practice puts the employers themselves in a position where these resumes and answers cannot possibly be read. Not carefully, not at all. Again no blame one way or the other. I'm just arguing that we cannot expect the employer to carefully consider all these applications. There is no point in being shocked / surprised / whatever by this. The sprayed and prayed applications will not be read carefully. The employer will find whichever shortcut to sift through the pile and will carefully consider only a handful of all these applicants. Or hopefully, will see the light and consider other kinds of applications - such as network leads (but there are other options.)

My argument is about what we do next. My answer is that it cannot be job postings and answers to job postings. That ship has sailed. (And nonetheless, congrats on your new job.)