My degree and experience is in management. I did the interviewing and hiring for my dept. I retired about 5 years ago, but I'm skeptical about this "can't find candidates with the right skills" explanation I'm hearing these last several years.
The impression I'm getting, admittedly from anecdotal evidence, is organizations have "streamlined" the interviewing process to make it easier for their HR depts. They appear to be using filtering algorithms based on their job descriptions. Consequently there is a large number of people getting overlooked for tech positions. If this is the case, then that explains the shortage. IOW, they've created a narrowly focused requirement for hiring. And I'm sure they're also limiting the pay which is another limitation for filling a position which allows them to say they "can't find candidates with the right skills."
When I was hiring people, I knew I would never find an exact fit based on the job description. IMO that's just not realistic. However, what was most important to me was how well the individual would fit into the dept. My emphasis was on personality and I had questions that were geared toward understanding that. Also when somebody interviewed for my dept, they had to spend time with several of the more senior people who were working there. Afterwards those people and I would have a discussion to compare impressions.
The point I'm trying to make is the emphasis was on how well the person worked with others. Their technical skills were important too, but I knew if they were clever (usually exposed via the resume and the interview questions) they could pick up whatever they might have lacked. And truth be told, every business has different SOPs, policies, etc. The new employee will have to learn something new no matter what.
The impression I get re today's HR hiring methods is they've chosen a lazy way to do it. I even hear ads on the radio promoting how a service will filter people for the hiring firm. I'm sure that one of the reasons for this approach is management has limited staffing for HR forcing HR to do more with less.
So the "can't find candidates with the right skills" excuse sounds bogus to me.