Would you say HVAC companies are more or less "entitled" to that labor/profit, compared to, say, a company that prints business cards for those kinds of small businesses?
Any business is entitled to the profit they’re able to compete for and satisfy their customers, HVAC, lending, printing, whatever, even selling pictures of your butthole on the internet.
When regulation serves to limit via licensing and multi-year apprenticeships is where you get into market distortions that sometimes serve consumers and sometimes harm them. This happens to some degree in licensed trades (price out a drywall crew, painting or carpet [not licensed or at least licensed without apprenticeship in most places] vs a plumber, electrician, or HVAC).
Yep, same story with solar rebates, most of it goes to the installer.
Home construction work is really interesting, because the transaction costs are so high around locating and comparing the service providers.
It is easy to say there isnt enough competition, but im not sure that is actually true. I think more likely is that most consumers dont collect 10+ quotes and compare, so the price signal is weak.
Part of the problem is that buying refrigerant requires a certification/license.
Also in Seattle, only an HVAC company can pull a permit for refrigeration, even though plenty of heat pumps/mini splits are pre-charged and you'll never need to touch refrigerant.
The EPA 608 universal takes about 90-120 minutes online and is free at SkillCat (no affiliation, but I tossed them $50 as a thanks). The 609 (for autos) takes way less time but costs $25 online.
I’ve bought refrigerants online several times over the years without showing any license (even though I hold an EPA 608 and 609). It’s legal to buy for resale, which is probably how suppliers get around checking.