That’s the general answer, and I agree with it.

I think it doesn’t work well in practice for a regulated/licensed trade (with enforced minimum apprenticeship times) when trying to do a temporary lump of conversion work (retiring working fuel boilers and replacing with heat pumps faster than would otherwise happen naturally).

As a mechanical engineer and hard-core DIYer, I can’t legally do it myself, nor get the local rebates if I do a pirate install, nor start a company to compete against the HVAC incumbents without hiring from the same limited pool of licensed HVAC techs those companies have.

Competition might work as an answer over a long period of time (with stable incentive programs).