Unless your existing taxi services were wildly over regulated, wildly profitable, or paid very well, that price reduction might be temporary. The cars must still be paid for and maintained and fueled. The drivers still need to pay for food and shelter. There is only so much room to move on costs.

It could well be that a globally managed booking system is enough to kick the tires out from under traditional taxis, but I think the other costs have a much greater role in final pricing than mere booking.