Ok, here it is:

1. Wireless is off for so many reasons.

Even if cost wouldn't be a problem, wireless has many other disadvantages.

First, it's not really wireless, you need to wire power, and cut walls.

Second, most of devices will spend their life deep in the junction box, or even cemented inside the wall. Having an external antenna for every one of them is impractical.

Third, no wireless standard is even 1/10th as reliable as wire. They are simply too complex.

Fourth, you want to have backup power for such vital things like HVAC in highrises without windows, security, and fire alarms, emergency water, and electricity cutoff, door locks, and intercom. This way, you need to have wiring anyways.

2. Star topology as I said hugely increase costs through: additional labour, cabling, cutting walls, switches, bigger junction boxes.

Main idea is that you don't want the builder to have to cut walls when they can not to.

2. For busses you have no alternative to CAN, or RS485 based busses, or multidrop ethernet hacks. Third is off because it's expensive (think of having 3 port T hubs for every device.) First is off because of bad hardware selection.

So we are left with many hacky RS485 based solutions.

Choose your poison:

Unreliable CSMA

Manual addressing

Super low performance

Polled nature

Near no existing ecosystem

In the end, MODBUS with hacks it was. The lesser of all evils.

4. It being a bus, and you having devices connected to other appliances, you have to provide electrical, and I/O isolation, as you don't want a random man plugging 220VAC into it in error, or deliberately frying all electronics in the highrise.

That's hugely expensive, and sometimes you want to power external devices through your box.

This necessitates to invent many case-by case compromise solutions.