We're explicitly encouraged to use Uber, Lyft and Airbnb. I work one of the SF tech firms with several thousand employees.
We use Concur and it's required for airfare but somewhat optional for hotels. If you're using a group conference rate or staying at an Airbnb, you're exempt from using Concur as long as the price isn't too much higher.
I use Uber everywhere over cabs but still generally stick for hotels for business travel. Probably half the trips in our company are to either NY or SF so I understand why they're encouraging lower-cost options in those two cities.
Other than conferences, all my business travel is to SF where I stick with the Westin at Union Square.