Unless you design your house and buy your furnitures taking these roomba into account, they get stuck nearly every where or at the first sock left on the ground by someone in your household. They have a number of wearable most owner will not even want to replace and will start being inefficient rather quickly. Add to that some battery wear and I don't think there is a lot of +5y old devices in the wild.
I and most people I know went back to regular vacuum cleaners. The thing is, those robots really don't solve a real problem as vacuuming and mopping are the easiest and quickest job when it comes to cleaning the house. Dusting all the furnitures + objects on top of them and cleaning the bathroom and toilets correctly are both much more time consuming and annoying jobs.