You can even see that problem get worse as people leave. Fantastic dev I worked with moved from Seattle back to India. She said that yes, she made more money in Seattle, but cost of living was so low in Bangalore that she effectively made a lot more money there. Coupled with her family being closer, it made perfect sense.
iPhones are cool, but houses are cooler.
And, from an investment point of view, maintenance may not be worth it if you believe that housing prices are too high and that a correction will be coming in the short to medium term. Why spend your own money on repairs if your house's value is going to tank in a few years anyway?
(mostly joking)
You don't give them enough credit. This process works for them sometimes. And sometimes is evidently enough.
Part of this complaining can be an attempt to influence/distort government policy, justify a flawed or exploitative hiring process, or managing who to blame when they miss a quota.
I definitely agree that what you said is part of reality for some companies, which is why I think it's important to aggressively point out that there are solutions when the "skill shortage" is brought up.
Additionally, if underpaying younger talent is prevalent, then all the more reason a company should offer competitive salaries to recent graduates when faced with a shortage. They'd start booking some easy wins.
This attitude has to change.
If a company can make significantly more money by hiring someone, then they should be aggressively increasing wages to signal to the market that they are serious. It's basically refusing to participate in the free market, or a complete lack of understanding of how markets work.
Business managers frequently act like they understand economics better than economists yet this attitude should telegraph a level of cluelessness that makes them unfit to manage a hiring process.
Everyone wants to pay less and get more talent. If you can't afford to pay more then compete on other aspects---allow remote work, more flex-time, and so on. Try something different in your interviews. Offer apprenticeships.
Sometimes it's not even a pure talent shortage that force increasing wages. In San Francisco the housing shortage and lack of support for new construction wipes out a lot of gains that come with higher salaries.