> The more efficient and feasible solution to these shortages is to incentivize citizens to enter these roles.

If one would purely go by the rules of the free market, the solution would indeed not be immigration, but either automating these jobs away, rationalizing them so you need fewer employees to handle the same workload or raise the compensations and non-payroll benefits to attract more (prospective) talent.

The problem is, it's one thing if you do that for air traffic controllers. Flights are too cheap anyway, making them a bit more expensive to pay for more ATC will also reduce demand which in turn would also have positive benefits on the environment (CO2) and airport residents (noise).

But for stuff like garbage disposal handlers, wastewater facility staff and other jobs on the high-ick, low-pay side of things? These are actually and literally vital for society to survive, but if prices were raised to reflect the fact that you need to pay people pretty huge sums of money to do these jobs? Barely anyone would remain to pay for these services.

In the end, immigration has been used by Western societies as a stopgap to avoid the inevitable conclusion that the wide masses by far do not earn enough money, and now that immigration is drying up - in the case of the US, from the political climate, in the case of Europe including the UK, many people from Eastern Europe going back to their home country during Covid and discovering life there has actually vastly improved over the last decades - the cracks are growing so large they can neither be hidden nor overlooked any more.