Such drones will be built but whether or not they will ever be used in the manner Jeff Holden envisions is another thing altogether. First there are some major technical hurdles to be overcome.
Battery technology needs to improve markedly. Just think about the logistics of an aerial fleet of taxis buzzing around overhead keeping them all from colliding with each other and terrestrial objects and needing somewhere to land along with the all noise they will make.
Amazon's delivery drones will be up and running before we see the Uber drone system up and running. Overcoming consumer resistance to a pilotless aircraft will also be an issue.
I'd be very surprised to see a fully working Uber style passenger drone system it in my lifetime. I'm always up for for surprises though.