It's actually build a better service, give each user subsidized (or free) rides so they get to experience how much better the new service is, then stop handing out free rides like candy.
Use VC money to put taxis out of business then jack up the price and let the service level plummet as cheap immigrants become the drivers.
When cable TV was installed in the UK - thanks to US investment - they dug up almost every pavement in towns and cities nationwide, call centres were local to their customers, the technicians were actual skilled employees who worked in teams of several people.
Jump forward a decade or two. They are deeply in debt. Call centres are outsourced and often abroad. Technicians work for contractors and have nothing invested in the business they represent. If you live a few meters away from a cabled street then there's virtually no chance that they will hook you up.
I personally use Uber because I hate calling a cab company, finding out it does or doesn't have a cab to send, figuring out the address I need it to come to, getting a very general estimate of when it'll be there (8-15 minutes), etc. With uber I drop the pin in the exact spot I want it, I know the minute my cab is there. If cab companies had an app like that, they'd have my business.