In addition to being unable to pay what the market demands, companies (from my anecdotal perspective) also don't have any desire to train new developers into positions.
It's not that they're unable to pay -- they choose not to.
I see so many companies that want something for nothing. They want the automation and savings from the systems that developers are building, they're just not willing to pay for it. But then ask them if they'd rather go back to the manual business process they were doing before (that doesn't require paying developer salaries) and they look at you like you're crazy.