I can think of very few business ideas that need $2 billion+ worth of runway before they are self-financing. It certainly seems it should be possible to build a ride brokering service with a fraction of that.
But I assume they got it because they could and not because they needed it.
It's also about a lot more than ride sharing. These companies are hoping to turn their LaaS (labor) into self-driving car fleets as soon as possible. A lot of that money is going to be poured into research.
But I assume they got it because they could and not because they needed it.