No way - $40B is just nuts, and I think underestimates the ability of other companies to get in on the action. Many of the drivers I've used have multiple smartphones running, one for each service, and just bounce around to whichever gives them bookings. Add in multiple new services - and Uber's growth will suffer.
Uber is totally worth $40B. They have a great brand and tbh that matters a lot. When you are looking for an alternative to a taxi, you will remember Uber and not their competitors. The article nicely compares Uber to eBay, who got a similar advantage. When eBay came out, there were a lot of other auction sites, but eBay became the household name. Uber is a true disruptor. The biggest taxi company that does not own a single taxi. If I could invest in Uber, I would.
Uber is a true disruptor but it can't be worth $40B! It's got massive growth but does it have the ability to keep control? Like mikehawkins I think the market share will dilute. Look at what happened with Meercat and Periscope.