simple supply/demand economics.
Raising prices amidst extreme demand is a good way to maximize profit on the supply you do have, but expanding your supply to fulfill demand is almost certainly the better course in the long run.
Uber is dropping their fares only for the duration of the taxi strike, ostensibly to make sure "ordinary folks can get around the city while the taxi drivers strike to get a fair deal."
During the strike (viz., the 'short term') there will likely be a shortage of cars, including uber cars. Lowering their prices will only make it harder to get an uber car during the strike.
Someone brought up that Uber cars are already hard to book (strike or no strike), and my point was that instead of raising prices to maximize profit, one would be much better served to expand the fleet instead.
In any case, even in the context of the strike, presumably Uber has longer-term plans than just tomorrow - raising their prices, while following the laws of supply/demand, is going to smack of gouging, and will naturally do far more damage in the long run than whatever extra profit they can derive.