To start, aircon is an incredible racket in general a lot of the time. Good companies exist, but lots of others, especially in the USA, have been bought up by big holding companies and converted in to profit maximization new-system sales machines. Techs get paid pretty poorly, and helpers get paid worse than mcdonalds/target in a lot of areas. There's not much financial incentive for someone to get really good at understanding residential a/c systems for repair/diagnosis anymore in most places.
Then to your tablet question: even on simple non-zoned systems, lots of manufacturers have totally moved away from oldschool thermostats that have simple fan/compressor/power/etc.. wires, in favor of "communicating" systems. "Communicating" means there's a proprietary protocol that their thermostats, control boards, and other misc electronics in compressor/condenser assemblies speak; for which there is no standard. A handful of modern advancements kind of necessitate this, such as variable speed compressors (yea, you could totally control that with normal electrical hardware, but....no one cares).
Couple all that with people willing to pay damn near anything to cool off when its 97f outside, and you end up where we are today.
This is why I chose to replace my basic forced air gas furnace and basic 16 seer single speed single stage A/C unit with the same thing. Every part on these is relatively simple, largely serviceable and every parts house coming and going will have something that fits. I disagree with others that any of the more fancy stuff is any more reliable (and Dad worked as an HVAC master tech for a long time and also agrees with this) and I can't believe people pay for more complicated stuff when so far as I have ever seen it's 90%+ snake oil and drives the initial price and the cost of repairs up astronomically, and largely cools or heats the house all the same. I am well aware that Bryant, Lennox, Trane, Mitsubishi and everyone else coming and going has got the more complicated garbage that talks something more complicated, I just really don't get why you'd double or more the cost of things when you can get something that just works for less. I also don't understand the obsession with "smart" controls on any residential single family home when a basic programmable thermostat already does basically everything.
I'm sure as everyone piles onto the mini-split hype train, there's going to be even more fleecing of homeowners for maybe middling quality hardware and installs. Someone (either the HVAC company owners or the hardware manufacturers or maybe both) is making an absolute killing on this; maybe it's time for a career change.
the one thing I'll say about some of the more complex systems is this: if you have a small/medium size house and can get by with a single zone, or need multiple zones but can/are-ok-with having a dedicated system per zone, I 100% agree with you. If you need a single system with multiple zones, the variable speed setups can be a lifesaver to make sure you can tune everything correctly for every combination of active zones without having intermittent head pressure issues; especially if you have any suboptimal ductwork.
> I also don't understand the obsession with "smart" controls on any residential single family home when a basic programmable thermostat already does basically everything.
don't get me started on this. all this "learn your schedule and adapt conditioning to match where you are" is literally the one thing you ARENT supposed to do with efficient heat pumps, which are becoming more and more common. You set it at a temp, maybe you let it bump up 1-2 degrees in the heat of the day and then back down later at night, but any more than that is LESS EFFICIENT and more expensive overall. I don't get it.
Then to your tablet question: even on simple non-zoned systems, lots of manufacturers have totally moved away from oldschool thermostats that have simple fan/compressor/power/etc.. wires, in favor of "communicating" systems. "Communicating" means there's a proprietary protocol that their thermostats, control boards, and other misc electronics in compressor/condenser assemblies speak; for which there is no standard. A handful of modern advancements kind of necessitate this, such as variable speed compressors (yea, you could totally control that with normal electrical hardware, but....no one cares).
Couple all that with people willing to pay damn near anything to cool off when its 97f outside, and you end up where we are today.