WTH there is no "available_state" for every entity?

I think it’s easy to explain with an example:

I have some integrations like Enigma2, PhilipsTV, PS4, etc, for devices that are connected to a smart switch that is powered off every time I’m not using them. I think this is something common for every home automation enthusiast.

The problem is that, as I can’t configure an “available_state” with a template or with a related entity state, I see a lot of errors on the logs trying to connect to these devices.

If a “available_state” was available, those logs would dissapear and Home Assistant will avoid a lot of tries of connections to these devices.

Maybe there’s something I can configure and I’m missing out, but I think it can be very useful!

What do you think?