Because most people aren't interested in buying a bunch of devices to plug in at the edges of their house on the off chance it'll catch a lost charged device reaching out via wireless instead of just cleaning ;).
Most frantinc searches of my phone happen as I'm about to leave the house in hurry. Cleaning is not an option then. I would have to be 'organised' which I absolutely abhore and want to avoid at all cost.
So far my solution was to just have a second phone in a fixed place so I can call my main phone and locate it by sound.
But the wifi triangulation thing sounds like way more fun.
Though if you’re in it for the fun factor then go for the wifi option!