The title is misleading; the author was using a ride sharing app, not a cab.
There is a correspondingly deliberate attempt to ensure that the two remain separate in peoples minds, to ensure that Grab, and the other "* sharing" apps, don't get the same regulations applied to them as the industries that they are trying to disrupt.
But make no mistake, the services that Grab/Uber/Lyft/other "ride sharing apps" provides is for 99.99% of consumers a direct, possibly cheaper, replacement for a cab service.
I think that, reading between the lines, this article is talking about that point. I know cab services are crappy most places, but ride sharing apps are cheaper precisely because they’re trying to build a market without any regulation and they’re undercutting cabs in part because cabs cost more. The business innovation of ride sharing apps is in externalizing the costs of ride sharing, from the maintenance costs of cars onto the drivers, to the lack of unions & benefits, to the “disruptive” startup mentality where Uber justifies breaking laws because it’s good for business, to lower regulatory oversight and fees.