Smoke alarm everything

Smoke alarms have fallen to the $15-$25** range and would probably be cheaper purchased in bulk, sans packaging*.

Why not offer lines of appliances with smoke alarms built-in like the ubiquitous digital clock? Loss-of-power scenarios could be accommodated with batteries (rechargeable or otherwise), or supplemented with traditional, battery-operated smoke alarms.

{*In fact, they'll probably never retail for less than about $12 even if they could because most people simply wouldn't buy/trust a $2 smoke alarm.)
(**All costs made-up in U.S. dollars}