you need collection from multiple nodes, aggregation, sorting and then distribution to multiple nodes.
uber model is likely flawed because there isnt enough volume to scale. without aggregation, you cant capture economies of scale. there isnt standardisation at source or end points to justify aggregation. the game is over before it starts to make $$.
my 2c.
on a related note and going back to the actual topic of discussion: this is why mobile delivery of vaccines door to door will work better than the public driving down to isolated hospital centers to be vaccinated.
at this scale...and for CA alone, it's 40 million residents...its never going to be possible to vaccinate us all. and also why africa and china and india(1.2, 1.3 and 1.4 billion people respectively) will be able to do a better job than the usa when it comes to covid. again.