The worst thing to happen to home automation was companies trying to lock customers into their ecosystem without greater interoperability.
It’s not just home automation, commercial automation is full of single source vendor ‘solutions’.
Building automation: Johnson Controls, Carrier, Siemens, Honeywell, Trane (and others) all provide proprietary controllers and software. There are some ‘open’ systems where multiple dealers sell a product line, Distech and Alerton are the big ones that I’ve seen.
Fire alarm: Johnson Controls (Simplex), Siemens, Honeywell, Bosch. Honeywell has their own internal product line that they sell, as well as two other lines that they have dealers sell (Notifier and Silent Knight).
Nurse call, duress, security, surveillance (and probably other low-voltage/control systems I’m not familiar with) have the same problems with proprietary systems.