I'm kind of in the 'build it bulletproof' camp. I use Crestron for this because there is a glut of product on the used market for a very good price that was thousands when new. Great stuff. I can then give someone a phone interface, or a simple handheld remote that works anywhere in their home, and drives the entire system. I have some of those old $4,000+ touchpanels in my storage area, and I'm thinking I may soon just throw them away. They don't measure up to my iPad control. I actually tend to throw them into areas where I want something that can just sit still and always be available. 10 years in my home, the one up in the playroom, that was over 5 years old when I got it (for free I think) is still working perfectly. How awesome is that? Also, the code I wrote for it? Still fully supported. I can edit it, change it up, all the rest. I've even used 20+ year old touchpanels in shop areas and such where nobody cares if they get damaged and I could replace it for under 50 bucks.
Yeah, homes can be retro wired, but if speaker wiring was done to industry standards (14/4 or similar) from a head end location, and cat-5/6 cabling to keypad locations, then everything can be upgraded. ABUS was one of those proprietary ideas that made the wiring easier, but didn't actually make things upgradable. You were locked in with volume controls that doubled as amplifiers. Less wiring expense, which is good, but far less flexibility, which is horrendous. Plus, the stupid reality of software support disappearing to really screw over the customer. *sigh*
I would probably dump the ABUS, and run some amplification from the head end through the cat-5 to the ceiling speakers. Not the most robust wiring, but then a iOS app to run the show with sources and a control system in the basement. It would work pretty well, but people would lose the 'local' inputs I expect. Instead, it would move to a Wiim or Sonos source (or several) to get multiple sources of audio everywhere in the home.