No, but unlike TVs they consume mere tens of milliwatts when the display is off (most of it going to maintaining the cellular connection), and their batteries would be dead within a couple hours if they used as much power as TVs are allowed to suck when "off"

It's certainly possible for a TV to be ready to be fully on within a second while consuming <1W; monitors do it all the time. But TV makers barely have the software expertise to respond to button presses within a second when on; developing responsive low power states is an order of magnitude harder.

Most large TV makers make smartphones too, so I doubt software expertise is the issue. Probably more about market forces. (Consumers don't generally differentiate TVs based on startup speed.)