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.