It's about professional companies doing unprofessional things.
It's really too bad that this code of ethics is limited to HVAC companies.
/s
The sad thing is, the professionals on here instead of universally condeming the ones giving their profession a bad name, double down trying to defend them and then personally attack others who communicate stories of more wrongdoing.
Maybe you missed it, but I do not and will not stick up for companies that do the wrong thing.
Unfortunately, the stance of one person, me, does not change how some of the largest and most brand recognized HVAC companies in my area operate (the ones with the professional sports advertising and all of the billboards). I have seen the work (but certainly not all of it), most of it that I have seen is ****.
I have seen the work in residential new construction, and while I am willing to generally defend the individual doing the work, unlike you, I also know that the quality (or lack thereof) of the installation in this instance is indeed dictated by the builder- that doesn't want to pay for HVAC work. And that the person actually performing the work must adhere to whatever the employer is dictating. It is saddening to see what passes for HVAC in a million dollar house.
I have personally done $15k+ CAST IRON boiler installs. You have no idea what is involved. I don't give a **** that you can buy the boiler at the supply house for $1,200.00. It is NOT difficult to hit that number. The stuff on "This Old House" has to be six figures.
You did not post the scope of work for the boiler install price that you are condemning.
I have no issues at all blasting you or anyone else complaining about prices or labor rates without a scope of work to back up these almost constant complaints about "pricing" and digs against contractors. The second most stupid thing is when a person starts a "what will it cost" thread (HVAC or not), and also has no scope of work, plans or specs. And then the people like you on this forum come in and say that it should only cost "X" (some number seemingly pulled out of thin air).
This forum/site should really prohibit pricing discussions on most construction type projects- or limit pricing discussions to those that include scope of work, plans and specs. If the goal is to "help" with HVAC issues, then pricing does not need to be discussed. Pricing is specific to each region. /rant
There are companies, and people here on this forum, that will slap in a condensing boiler in place of a cast iron boiler, and not do ANYTHING to the piping. I have seen the questions posted here in this forum. I will not walk someone through an install. The directions are in the installation manual. If the individual does not want to read it, or cannot read it, that's not my problem.
The parts to correct a bad piping job are thousands of dollars by themselves, plus installation. Whether or not a condensing boiler is being installed. Most of the pictures I see here of installs, are not installed correctly.
There are companies, and people on this forum, that will not install it properly. The employee is typically told what to do and how to do it, which is often dictated by the bid and scope of work.
Yup, there are those that know better, and still **** it in. THIS IS NOT NOT LIMITED TO HVAC WORK.
The tax incentives do not care if the boiler is suitable for the installation, or not. The unknowing public will ask for such installs because of the tax credit. Shoddy companies will drop hints to try and make the sale, but as I have stated before, that's capitalism, bud. It is also a result of a KPI driven work/salesforce.
Same thing for heat pumps. People ask for them because of the incentive advertising. Shoddy HVAC companies do not do a load calculation or figure the thermal/economic balance point. That is another common topic here. ******** DIY'ers think anyone can put one in and have it work. Obviously not, based upon the posts in this forum.
HVAC is not the only industry with pricing that moves to capture increased profits from incentives. Capitalism at work.
I can easily see $3 to $5k in labor to install a "mini split". The company I work for, installs them. The pipefitters do the refrigerant piping, an electrician does the wiring and I do the start up. Unlike the other two groups, I AM capable of doing it all myself. If someone is paying a company to do this work, it's REALLY EASY to hit those numbers, and in some situations, the work has to be broken out just like I wrote it above, although some fitters can do the start up too. Fortunately, where I am, they do not want to, or can't do it. If I figure my time at company labor rates, guess what, the end number is around the same.
I have heard other blowhards on the job bragging about "4 hour furnace and AC changeouts". I offered one guy $1,00.00 to come and watch, so I could see what I am obviously doing wrong, and he never took me up on my offer.
For the record, I have no problem calling out installation mistakes at my employer. Some of it is due ingrained bad practices and/or not reading the manual. If my name is on it somewhere, I will speak up. I hate coming in behind a couple of other trades to do the start up, because invariably, someone has fucked up something and stuff isn't pre-checked before the ceiling is up and the GC is trying to turn it over, and I have to figure it out.
I have lost a job or two by "doing it right" or asking those questions that are swept under the rug. There can be a real cost for sticking up to your beliefs, and sometimes it isn't worth it when there are bills to pay, and I'm not responsible for the warranty calls. Hate to say it, but that's the truth. Even where I am at now, issues have to be brought up carefully, but the owner is also more receptive to "doing it right" than any other place I have worked at.
A bigger issue than your boiler or mini split pricing is the cracked heat exchanger scam.
Shoddy sales techs and shoddy companies will condemn a heat exchanger with zero proof. No pictures. No combustion analyzer. And they are very good at scaring the homeowner into replacing a system that may be functioning fine, with absolutely zero heat exchanger (HX) issues.
Hell, there is even an industry guideline to determine if the HX is a problem: AHRI Guideline X.
I am a firm believer that combustion appliances and the associated venting and makeup air systems need to be checked each season with a combustion analyzer to ensure that the stuff is working/venting properly. I have been on commercial jobs where the boiler room is over 300 ppm CO because the makeup air system is not working.
Please continue 
I think these guys should open a HVAC business and with their vast knowledge they will corner the market in no time. Do everybody a favor and save the general public from these savage HVAC businesses! Sounds like there's a bit of jealousy in their complaints.