With a lot of hiring processes I get the impression of filters tuned to the exact match of skill and experience requirements, plus some padding. This is systemically bound to fail because the candidate pool for any one cross section of a growing area is going to be small enough to put you in competition over the qualified candidates. As well, it tunes for a stodgy "best practices" mindset, with no chance of spreading skills diversity through your team.
For a field requiring some creativity as well as learned knowledge, enthusiasm and willingness to learn really matters, and the easiest way to induce enthusiasm is actually to go a little off of the mark and present candidates with an opportunity to learn the role based on their existing strengths. That presents some risk, and it's much harder to make it work as you go for "senior" candidates. But case-by-case, there are always ways to offset that risk if you are creative enough - better ways than putting folks who claim to know everything under the microscope in order to fail them as fast as possible, a process which builds a high level of mistrust.
One reason you put filters is to import foreigners. I haven't seen the US side of things but in other locations I've worked, you are required to list jobs on a national jobs database for a couple of weeks first and in theory to prove you couldn't find locals before hiring foreigners. The H1B system looks similar.
If you already have a candidate in mind, making the JD fit their CV both repels other qualified local candidates ("it says 4.5 years of Erlang backend experience, I'll get rejected") and makes it easy for you to justify the foreign hire. There's usually someone in HR who used to work for the relevant government ministry who will tell you exactly how to word the job ad and later visa application and appeals.
Note in case not obvious: I'm not advocating doing this.
For a field requiring some creativity as well as learned knowledge, enthusiasm and willingness to learn really matters, and the easiest way to induce enthusiasm is actually to go a little off of the mark and present candidates with an opportunity to learn the role based on their existing strengths. That presents some risk, and it's much harder to make it work as you go for "senior" candidates. But case-by-case, there are always ways to offset that risk if you are creative enough - better ways than putting folks who claim to know everything under the microscope in order to fail them as fast as possible, a process which builds a high level of mistrust.