I wounder how it would effects the earning of those taxis drivers? Can switching to electric cab increase their income?

It will be really great too see their income (Not just financially) increased by switching to electric vehicles. Because that could give people stronger motive do to this kind of switch than government subsidy.

A taxis company in our city renewed their cabs recently, unfortunately they picked rather old cheap tech cabs that burning petrol + natural gas. If Shenzhen's taxis companies and drivers can receive benefits from such, everybody will eventually follow the trend.