Do you think those devices boot every time you send them an input, or just when they're plugged in? Unless you're turning the TV on and off thousands of times per day this would be unnoticeable.
The original comment you replied to mentioned cars in the context of booting devices often, so I simply pointed out that yes, actually it makes sense to boot up some devices when they go to receive input and not to leave them in standby as you suggested. In a vehicle that may sit off/idle for several weeks, it's best not to drain the battery unnecessarily.
If someone did not optimize this this might indicate other optimizations
But yes, I also hate when home router takes forever to reboot and reconnect