Not exactly true. I had a Samsung robot vac about 6 years ago and it sucked (not in the way it was supposed to!), constantly getting stuck, eating cords, not finding it's way back to the dock, etc.

Newer vacs are WAY smarter, although you need to do some research and some are pricey. I got a Roboroc now and it's amazing. It's gotten stuck maybe twice in the 6 months I've had it, it keeps the floors spotless by vacuuming AND mopping, and is smart/capable enough to recognize floor types and lift the mop up when it hits carpet. If I move furniture around it instantly recognizes it and updates the map, it'll notice objects on the ground, recognize what said object is (cord, shoe, shirt, dog shit, etc) and both avoid it and let me know what it is. It empties its own bin, washes and dries its mop, and empties and fills its dirty/clean water tanks. I have a golden retriever who is constantly tracking dirt and fur in, but this robot keeps my place spotless with essentially no vacumming needed from me. With proper maintenance the little dude is a god send.