In the case of cable boxes they're not always doing nothing - updating code and EPG for example. They could in principle have an on/off cycle to do this but synchronising that would get complicated - due to the huge numbers of them, anything that caused a tiny percentage of issues would affect a significant number of customers.
Even issues like thermal cycling could become significant, so for reliability, leaving them always on apart for the display is probably the best approach.
Well Mike I certainly respect your opinions here. But let's look at it this way - we were talking about saving costs of production, as the other person said
"yea eliminate the display parts". As I found out, the thing is not really turned off unless the plug is pulled. It uses 13W on and 12W "off". My Killawatt is really flickering between 12W and 13W so I'd give it 12.5W when "off". It's probably because of the points you raised.
So why do they even have an "off" function (button) on the box? Why spend money on an "off" hardware button? Why not just design it so the cable installer plugs it in and it's on all the time (which for all practical purposes it is anyway). The old boxes were the same way, they were always really on, except they had a clock at least for the people to use if they wishes.
Good. We have on screen displays for channel info, smartphones and watches for the time. Why do we need yet *another* clock / indicator on a product, adding cost and power consumption for no apparently good reason?
I forgot this point last time I responded. When my 85 yr old mother was alive and messed up the settings of her cable box or TV she'd ask me to come over and fix it. She'd always say "Make sure the cable boxes (she had two) are showing the time!". Those were her clocks. Now you can come back and say "Your mother needs to get with it and get some other clocks!"
The point is, even though you and I can get along with technology changes some senior citizens want things the old way. They
do not like changes even as small a thing as removing the clock from the cable box. When I asked the cable installer about the missing display he confirmed that many of their older customers did not like the display removed.
Point is, let's let little things be for a while longer until an older generation passes, before we save a few cents and remove little things like clocks they like to use from their lives. Is that really too much to ask?