What exactly is a smart home and can it be retrofitted?

... which, however, satisfies 95% of users completely because a) their expectations are not higher and b) the budget is allocated to more important things.

Smart Home is nothing more than a (nice) gimmick. No matter how simple or complex the installation is.

More than a (nice) gimmick, smart home is not.

No matter how simple or complex the installation is.

For everything listed above, the offerings from the major players in the smartphone market are sufficient. Apple HomeKit could represent all of this if you pay attention to HomeKit compatibility when selecting the roller shutter drives. It probably also works with Alexa, but I have no experience with that.

- Roller shutters, for example, with Homee or Fibaro for direct installation or retrofitting on conventional switches.
- Philips Hue via HueBridge in HomeKit.
- Various providers for door/window contacts (e.g., Eve).
- Various doorbell systems such as Netatmo or Doorbird available.
- HomePod as a speaker for internet radio or Apple Music.

Everything else (sockets, motion detectors, smoke detectors, etc.) is available for purchase and retrofitting at the electronics retail store.

In the Home app, you can then set the desired rules and automations. Another iPad mounted on the wall as a control center, and the whole thing works even when you are outside the home network.

We probably live in different times and on different planets.

Well, if you've never lived in one and have no interest in it, that might be true.

With complexity, the possibilities of the system also increase quadratically without quality loss and with a progressive decrease in necessary human interventions/actions.

But those who do have an interest in something "better" should inform themselves and then buy, not blindly grab something off the shelf.