Unless the older equipment is better able to handle power issues - as was indeed one of your arguments earlier (either here or in the LED thread)...?
More robust, versus more modern (efficient) and less robust...?
I honestly doubt it. In the LED thread, we were talking about two different technologies, comparing incandescent to LED with regard to how well or poorly it handles over-voltage. But that probably doesn't extend to "heat pump versus heat pump". Besides, not all of my HVAC heat pumps are new, they were installed: 1986, 1995, 2012, 2015, 2020, 2023. None have failed, but the 1995 unit was replaced with the 2020 unit, due to a leaky condenser coil.
I've been thinking back thru the failures that I can remember, and they are as follows:
1. 2009 or 2010 vintage KitchenAid side-by-side, compressor failure. The unit was low on refrigerant, and this spurred the compressor failure. Repair tech was confident it was caused by low refrigerant, not power issues.
2. 2011 or 2012 vintage unit, would need to dig to even find the brand. Cause of failure not diagnosed, since it was out of warranty and I was too busy to dick around with it.
3. 2019 unit, maybe Maytag(?). Failure was problematic condensate drain causing frequent flooding on our floor, starting just a few months after installation. Dealt with thawing it and clearing it several times over 3 years, before getting frustrated and just asking dealer to cart it away and landfill it.
4. 2022 LG, seemed like a cooling fan failure. Ultimately not diagnosed, since dealer needed 10 days just to send a warranty repair tech, to tell us
if it could be repaired. Predicted another week or two past that to order parts and execute repair, and we just couldn't be without a refrigerator for 3-4 weeks, so trashed it even thought it was still under warranty.
5. 2024 GE, working okay so far, but starting to make some weird noises while running.
So, of these four failures (and one pending), it seems the 2022 unit
might be related to power. Possibly even the 2011/12 unit, but unlikely. The others do not appear to have any relation to power quality, but to be fair, probably only the older two were related to refrigerant load.
Also, to be fair, I said "more than one refrigerant tech" told me it was related to the amount of refrigerant loaded into the system, which is only half true. One technician indeed told me that with regard to a failed refrigerator, but the other was actually referring to a failed dehumidifier I had asked them to dispose of, when making the same statement. We run 3 dehumidifiers in our basement, not that it's very wet, but it's broken up into three distinct spaces by thick stone walls. One unit is from the 1990's and might outlive me, but looking at my Amazon purchase history, I can see I'm replacing one of the other two every 2nd year.