Self-driving cars have long been a staple of science fiction, perpetually just a “few years” away. But, they really have arrived (and by arrived, we mean working in a few cities in the US). Indeed, Waymo, the driverless vehicle venture owned by Alphabet, is now providing over 100,000 robo-taxi rides per week, according to a LinkedIn post by the company's co-CEO. 

At a round number estimate of $20 per ride, that could be worth ~$100 million a year in revenue to Alphabet. Not bad, but Waymo is still burning a massive hole in Alphabet's pockets, with the tech giant announcing a further $5 billion investment into Waymo, which is now in its 15th year, just last month.

Of course, just because self-driving cars can work, doesn’t mean they always do.