Using a system like Z-Wave you can already do this. The problem is that as you need a lighting controller, multiple motion sensors and a base station it's not cheap - mainly due to licensing fees.
I did that a bit more than decade ago with misterhouse using linux on my basement fileserver and X10 devices. Now I'd use insteon because its transport protocol is more reliable. AFAIK there are no license fees.
The expense is in labor. Set up and aiming IR sensors takes more time than writing the "program" for misterhouse. The inevitable labor expense of troubleshooting and fine tuning is huge. This is the main limiter for my own home automation. In the long run controlling my tropical fish tank and the security sensor lights that light the walk from my garage to the house pays off. My hallway to the bathroom doesn't pay off for labor. I hooked up the basement door sensor and got it to work and still haven't hooked up or automated the basement stairs light yet. Its a labor cost thing.
There are also severe depreciation/lifespan issues... a lot of non-automated hardware is designed, built, installed and paid for on the assumption of a 20-30 year working life. Most of the "new wave" of home automation is built to last till the runway runs out or the aquihire, maybe a year lets say. In the long run that is not going to help the entire market.
I did that a bit more than decade ago with misterhouse using linux on my basement fileserver and X10 devices. Now I'd use insteon because its transport protocol is more reliable. AFAIK there are no license fees.
The expense is in labor. Set up and aiming IR sensors takes more time than writing the "program" for misterhouse. The inevitable labor expense of troubleshooting and fine tuning is huge. This is the main limiter for my own home automation. In the long run controlling my tropical fish tank and the security sensor lights that light the walk from my garage to the house pays off. My hallway to the bathroom doesn't pay off for labor. I hooked up the basement door sensor and got it to work and still haven't hooked up or automated the basement stairs light yet. Its a labor cost thing.
There are also severe depreciation/lifespan issues... a lot of non-automated hardware is designed, built, installed and paid for on the assumption of a 20-30 year working life. Most of the "new wave" of home automation is built to last till the runway runs out or the aquihire, maybe a year lets say. In the long run that is not going to help the entire market.