[exogenousdata]

Or you could you allow the market to price those professions. If enough 60/70 year-old plumbers retire and there's no one to pick up the slack, those costs will rise and people will take those professions. Or someone will innovate in the space and make those professions different and more efficient.

The alternative is a top-down approach that requires policy-makers to pick winner & loser professions. Imagine being given the task of investing tax-payers money into incentive programs for trades/professions? How do you know which ones will be viable in 10 years time and which ones will be obsolete?

I'm not recommending a fully market-ist approach. But market forces can help appropriately price scare resources (professional services, in this case).