Apple replicating their car failure when they could just buy iRobot.
iRobot is a company that currently loses money. For the last 12 months, on revenue of $890m, it lost $264m. Its gross margins are just 22%. No amount of Apple fairy dust will make iRobot fit into the Apple ideals for profit margins.
Apple's failures in the self-driving car endeavor might have been partially Apple's fault. However, there are currently zero successful companies in this market, and none expected in the next few years. That's an indication that the main problem was that the technology for the market is not sufficiently mature and furthermore that it likely won't be for quite a while.
Of all companies, Apple should understand how technology maturity is the difference between the Newton and the iPhone. Apple's problem is that the technology is not ready for home robots, self-driving cars, or wearable headsets, at least not in a way that will produce iPhone-like profits.